# GMATPREP2

Amrabdelnaby posted a new topic called remainders and divisibility in the GMAT Math forum
“If x and y are integers, what is the remainder when x^2 + y^2 is divided by 5? 1) x-y divided by 5 the remainder is 1 2) x+y divided by 5 the remainder is 2”
January 11, 2016
Amrabdelnaby posted a reply to rates, productivity and labor cost in the Problem Solving forum
“Marty, The reason why I thought it would be insufficient is that the statement said greater than or equal. for example b can be any number greater than 50. it can be 500. same goes with c! the other way to think about it, is to say when the minimum value for b is 50, the minimum value for c ...”
January 11, 2016
Amrabdelnaby posted a new topic called R and S scale in the Problem Solving forum
“A certain quantity is measured on 2 different scales, R scale and S scale that are related linearly. Measurements on R scale of 6 and 24 corresponds to measurements on the S scale of 30 and 60, respectively.what measurement on the R scale corresponds to measurement of 100 on the S scale? 20 36 ...”
January 11, 2016
Amrabdelnaby posted a new topic called rates, productivity and labor cost in the Problem Solving forum
“Hi Pros, COuld you please explain to me the logic behind this question? coz when i plugged in numbers i found the answer is E! At RW Press, the advertising rate, a, is inversely proportional to the productivity measure, b, which, in turn, is inversely proportional to the labor cost, c. Is the ...”
January 10, 2016
Amrabdelnaby posted a reply to Tough one! in the Problem Solving forum
“Hi Guru and Brent, I think I can solve it as well without neither venn nor double matrix. I remember that Guru solved a similar one before using a simple equation: total yes = yes M + yes R - yes both total yes = 500 + 400 - 300 = 600 hence not yes is equal to 200 i got yes both by ...”
January 9, 2016
Amrabdelnaby posted a reply to Tough one! in the Problem Solving forum
“Hi Brent, I am very well aware of the double matrix method, yet i did not use it in here because i got bugged by the fact that there are 3 scenarios not only 2. I didn''t think of the fact that I could merge no and not sure into one scenario. Thanks for the enlightenment.”
January 9, 2016
Amrabdelnaby posted a new topic called Tough one! in the Problem Solving forum
“Pls help”
January 9, 2016
Amrabdelnaby posted a reply to Chetan Bhagat in the Sentence Correction forum
“Hi Jain, Which refers to the books not to Chetan. the sentence is basically saying the books of ( some person), which (abt the books) are bla bla bla, are more popular. so here the message is saying the books are more popular; which here refers to the books; it is describing the books, red and ...”
January 9, 2016
Amrabdelnaby posted a new topic called factorization in the GMAT Math forum
“Hello Pros, My questions is regarding statement 1 What is the value of 5x^2 +1? 1) x^3 - x^2 - 9x + 9 = 0 my approach yielded that it is sufficient; however the OA says that it is not. Here is what I did x^2(x-1) -9(x-1) = 0 x^2(x-1) = 9(x-1) divide both sides by x-1 x^2 = 9 ...”
January 9, 2016
Amrabdelnaby posted a reply to Jon Clark's Theory in the Reading Comprehension forum
“Number 124 is B not E. I revised it again today.”
January 8, 2016
Amrabdelnaby posted a reply to typical intervention in the Sentence Correction forum
“Parallelism Remove the fluff and then u must have the following Can have ........ and can last.........”
January 8, 2016
Amrabdelnaby posted a reply to doubt SC A 7 in the Sentence Correction forum
“I thought about b and c for sometime then I decided to remove the fluff in both sentences and look at them like this: Its ability to attract and to convince vs whether it can attract and convince The second one (c) seemed more appealing and correct I see ur concern that c might have a double ...”
January 8, 2016
Amrabdelnaby posted a reply to Economists in the Sentence Correction forum
“that, to define the set of factors being discussed. The point is not that inflation is one of the factors, which seem to indicate that an economy might be headed for a recession. That does not make sense, and if we remove the modifier, we get this sentence that does not express what the sentence ...”
January 8, 2016
Amrabdelnaby posted a reply to Handwriting analysis has recently been boosted by the invent in the Sentence Correction forum
“When "that" is an object we can eliminate it but when it''s a subject we have to keep it Here it was an object so it was ok to eliminate it Also option b was redundant; a conveyed the same message in a more concised way.”
January 8, 2016
Amrabdelnaby posted a reply to IT and THEIR in the Sentence Correction forum
“I''m surprised that it is b. it defies the rules of parallelism! I also thought its d actually? R u sure abt the OA?”
January 7, 2016
Amrabdelnaby posted a reply to cod, haddock and monkfish in the Sentence Correction forum
“I agree, this is the best answer choice and it also provides a correct and logical comparison”
January 7, 2016
Amrabdelnaby posted a reply to Jon Clark's Theory in the Reading Comprehension forum
“Took me 19 min to crack I think the answers are C C B A E D A C Right?”
January 7, 2016
Amrabdelnaby posted a reply to OG Verbal ED2- Life on Mars in the Reading Comprehension forum
“The answer to ur 2 questions is here been on Earth for 13,000 years, suggesting to some scientists that its PAHs might have resulted from terrestrial contamination. However, McKay’s team has demonstrated that the concentration of PAHs increases as one looks deeper into ALH84001, ...”
January 7, 2016
Amrabdelnaby posted a reply to OG Verbal ED2- Life on Mars in the Reading Comprehension forum
“The answer to ur 2 questions is here been on Earth for 13,000 years, suggesting to some scientists that its PAHs might have resulted from terrestrial contamination. However, McKay’s team has demonstrated that the concentration of PAHs increases as one looks deeper into ALH84001, ...”
January 7, 2016
Amrabdelnaby posted a reply to Target Question & DS question in the Data Sufficiency forum
“The only possible way for 4x to be less than 3x is when x is -ve. so lets look at statement 2 2x - 3 < 2 after adding three to both sides u get 2x less than 5 which means that x is less than 2.5 x here can be any number less than 2.5, positive such as 1 or 2 or even a fraction or ...”
January 7, 2016
Amrabdelnaby posted a new topic called counting zeros in a terminating decimal in the Problem Solving forum
“Hello Pros, in counting zero digits in a terminating decimal, do I also count the zero on the left of the decimal? for example would it be proper to say at 1/4 has one zero digit since it is equal to 0.25? or do we only count the zeros on the right of the decimal and hence we would consider ...”
January 7, 2016
Amrabdelnaby posted a new topic called Machine x & y in the Data Sufficiency forum
“Dear Pros, Could you please tell me if I did the calculations right? even though I got the answer right, but I just want to make sure that my thinking is also right. Machines X and Y produced identical bottles at different constant rates. Machine X operating alone for 4 hours filled part of a ...”
January 5, 2016
Amrabdelnaby posted a new topic called counting a 3 digit number greater than 700 in the Problem Solving forum
“Dear Pros, Pls tell which part of my calculation is wrong in answering the following question: Of the three digit integers greater than 700, how many have two digits that are equal to each other and the remaining digit different from the other two? 90 82 80 45 36 Here is how i ...”
January 5, 2016
Amrabdelnaby posted a reply to Probability - Monty Hall - Very Tricky in the Problem Solving forum
“Guru, I see your logic. one final question though The probability of the third event is one only if the event is sure to happen. this means that when he switches doors, he knows for a fact that he will find the prize, which is not the case. so for example Bear with me and let me know ...”
January 2, 2016
Amrabdelnaby posted a reply to Data Sufficiency Problem 156 in the Data Sufficiency forum
“Hello, First, We need to know basically if are numbers in the set are the equal. If all numbers in the set are equal then any number is equal to the mean. for example consider this set {6,6,6} this set has 3 sixes, the mean of them is (6+6+6)/3 which is also 6. now lets examine each ...”
January 2, 2016
Amrabdelnaby posted a reply to M in the Problem Solving forum
“Hello Brent, The second part of the question says another 40 km for 5 hours. 5 hours was the time not the speed; hence it yields to 8 kn per hour again. hence the average speed should be 8km/hr. Right?”
January 2, 2016
Amrabdelnaby posted a reply to A very hard, above 700 DS question from OG 12 in the Data Sufficiency forum
“I think the logic behind this question is very simple although it appears from the first glance to be terribly difficult. basically statement 1 tells us what happened from jan to may (deposits) but doesn''t tell us what happened afterwards. and statement two tells us what happened from june ...”
January 2, 2016
Amrabdelnaby posted a reply to Probability - Monty Hall - Very Tricky in the Problem Solving forum
“Now after giving it a second thought I actually think that the probability should be 1/2 since the guy is only left with two doors. although the contestant chose the door, he didn''t open it and since one of the three doors were opened by the host, now the contestant is left with 2 doors only. ...”
January 2, 2016
Amrabdelnaby posted a reply to Probability - Monty Hall - Very Tricky in the Problem Solving forum
“I think it''s 1/4 Here is how i thought about it first his probability was 1/3, but after the show host opens for him one empty door, the contestant''s probability of finding the prize becomes 1/2 now to the second stage, the contestant decides to change doors so we multiply his first ...”
January 2, 2016
Amrabdelnaby posted a reply to Factors, multiples, and divisibility in the Problem Solving forum
“I have 2 questions regarding this. Why did you not include the 19 in your listing? and what does the sum of positive multiple of 2 and sum of positive multiple of 4 mean? Pls explain Thanks”
January 2, 2016
Amrabdelnaby posted a reply to OG 130 in the Data Sufficiency forum
“Ok. I had a very different approach that made me think that statement 1 is sufficient. Please tell me what i did wrong here. I thought of 2 adjacent sides have areas of 15 and 24 then the following must be true: LW = 15 or 24 WH = the other number LW x WH = 15 x 24 the prime ...”
January 2, 2016
Amrabdelnaby posted a reply to OG 13 133 in the Data Sufficiency forum
“Brent, I dont understand why in your approach you ruled out scenario one in statement one? how did you assume that the hundreds digits of y and z don''t add up to more than 9?”
January 2, 2016
Amrabdelnaby posted a reply to Determining zero and non zero digits in a terminating decim in the Problem Solving forum
“Ok, So when counting the number of zeros in a number, I shouldn''t include the one on the left of the decimal point? As for your question, 1/10 has no zeros to the right of the decimal point; it has one non zero digit, one. 1/100 has one zero to the right of the decimal point and one non zero ...”
January 2, 2016
Amrabdelnaby posted a reply to Determining zero and non zero digits in a terminating decim in the Problem Solving forum
“Ok then. Correct me if I am wrong pls :) 1/ (2^17 x 5^11) lets work out the denominator first. 10^11 (2^6) --> 10^11 has 11 zeros now lets focus on 2^6 in the denominator 1/2 = 0.5 1/2^2 = 0.25 1/2^3 = 0.125 1/2^4 = 0.0625 1/2^5 = 0.03125 1/2^6 = 0.015625 --> ...”
January 1, 2016
Amrabdelnaby posted a reply to Take home pay in the Problem Solving forum
“Thanks for the explanation Rich. I have a problem I need to ask you about. Usually, if not always, when I solve maths problems, even those with high difficulty, I tend to find my way through much more easily when I am solving them casually than when I am doing a diagnostic test, to the extent ...”
January 1, 2016
Amrabdelnaby posted a new topic called numbers on the number line in the Problem Solving forum
January 1, 2016
Amrabdelnaby posted a new topic called pigs and cows in a farm in the Problem Solving forum
“Of the 60 animals in the farm, 2/3 of the animals are either cows or pigs. How many of the animals are cows? 1) the farm has more than twice as many cows as it has big 2) the farm has more than 12 pigs Pls explain”
January 1, 2016
Amrabdelnaby posted a new topic called prime factor of h(100) +1 in the Problem Solving forum
“This made my mind squeeze like a lemon :) Pls help :) For every positive integer n, the function h(n) is defined as the product of all even integers from 2 to n inclusive. if p is the smallest prime factor of h(100) + 1 then p is A) between 2 and 10 B)between 10 and 20 C)between 20 and ...”
January 1, 2016
Amrabdelnaby posted a new topic called m+z>0? in the Problem Solving forum
January 1, 2016
Amrabdelnaby posted a reply to Take home pay in the Problem Solving forum
“Yes I was :) Thanks”
January 1, 2016
Amrabdelnaby posted a new topic called Take home pay in the Problem Solving forum
December 31, 2015
Amrabdelnaby posted a new topic called Determining zero and non zero digits in a terminating decim in the Problem Solving forum
“Dear Pros, I have a conceptual question. How do we determine the zero digits and non zero digits in a terminating decimal? for example, how do we determine the zero and non zero digits from the decimal 1/(2^17 x 5^11) I thought about it in an intuitive way. First to determine the ...”
December 31, 2015
Amrabdelnaby posted a new topic called Counting in the Problem Solving forum
“If 4 points are indicated on a line and 5 points are indicated on another line that is parallel to the first line, how many triangles can be formed whose vertices among the 9 points? 20 30 40 70 90”
December 30, 2015
Amrabdelnaby posted a new topic called Computer store in the Problem Solving forum
“Dear Pros, Could u pls help me with this? Thanks http://s30.postimg.org/yuarnacel/DS1.jpg”
December 30, 2015
Amrabdelnaby posted a reply to Word problem in the Problem Solving forum
“Hi Rich, I have taken 2 CAT exams, scored 580 in the first, learnt some mistakes and then studied again and took the 2nd one after 6 days and scored 630. I am planing to take the GMAT exam on the 12th, and I am totally dedicated to it, doing nothing else except studying. I think it''s also ...”
December 30, 2015
Amrabdelnaby posted a reply to Rectangle inscribed in a radius in the Data Sufficiency forum
“Thanks alot Matt for the explanation. Could you tell me what exactly i missed in doing the plug ins? or why they did not work? Thanks”
December 29, 2015
Amrabdelnaby posted a new topic called Rectangle inscribed in a radius in the Data Sufficiency forum
“Dear Pros, Could you please help me with this? A rectangle is inscribed in a circle of radius R. If the rectangle is not a square, which of the following could be the perimeter of the rectangle? A) 2r rt3 B) 2r (rt3 + 1) C) 4r rt2 D) 4r rt3 E) 4r (rt3 + 1) I solved it using the ...”
December 29, 2015
Amrabdelnaby posted a reply to Word problem in the Problem Solving forum
“Hi Rich, I''ve been studying for about 3 months now, intensively. My last score was 630 in Kaplan, and I am aiming for 760+ I will do another CAT exam on the 31st and will let you know the updates :)”
December 29, 2015
Amrabdelnaby posted a new topic called Revenue, Profit & Expenses in the Problem Solving forum
December 29, 2015
Amrabdelnaby posted a new topic called Powers and integers in the Problem Solving forum
December 28, 2015
Amrabdelnaby posted a reply to Word problem in the Problem Solving forum
“Hi Rich, this question is from Vertial''s prep question bank. The truth is, I felt that their questions are difficult to comprehend. I started to doubt that these type of questions - by this I mean wording - would face me in the GMAT offical exam; I have went through the entire book of the ...”
December 27, 2015
Amrabdelnaby posted a reply to Prisoners in the Data Sufficiency forum
“Why in case two the number of prisoners is 5 not 6?”
December 27, 2015
Amrabdelnaby posted a new topic called Gurby & Gus in the Problem Solving forum
“I always get confused in these kind of problems and end up spending too much time on them and still getting the answer wrong! If you could please explain to me the solution and the concept/methodology I should use when tackling these kind of questions, I would be thankful :) After an attempted ...”
December 27, 2015
Amrabdelnaby posted a new topic called number properties in the Problem Solving forum
“I need an explanation for for this please. When a bigger number is subtracted from a smaller number, how can we calculate the units digit? The last digit of 12^12 + 13^13 – (14^14 × 15^15) = 0 1 5 8 9”
December 27, 2015
Amrabdelnaby posted a new topic called Word problem in the Problem Solving forum
“Pls help with this. A soccer store typically sells replica jerseys at a discount of 30 percent to 50 percent off list price. During the annual summer sale, everything in the store is an additional 20 percent off the original list price. If a replica jersey''s list price is $80, approximately what ...” December 27, 2015 Amrabdelnaby posted a reply to finding the non integer in the Problem Solving forum “Thanks Mitch, i actually assumed that x is an integer and then thought that if 9 is a factor if 2x then 9 is hiding in the prime factorization of 2x. hence prime factorization of 2x would be: 2 . 3 . 3 and some other numbers and prime factorization of x would be : 3 . 3 . and some other ...” December 26, 2015 Amrabdelnaby posted a new topic called Geometry in the Data Sufficiency forum “Pls Urgently Help” December 26, 2015 Amrabdelnaby posted a new topic called finding the non integer in the Problem Solving forum “If 9 is a factor of 2x, then which of the following may not be an integer? A) 6x/54 + 2x/3 B) 4x-18/9 C) 2x-27/9 D) 81-4x^2/81 E) 2x-3/3 Here is my thought process: If 9 is a factor of 2x then 9 is hiding in the prime factorization of 2x 2x: 2 x 3 x 3 x.... other unknown ...” December 26, 2015 Amrabdelnaby posted a reply to GMATPrep -EXPERT HELP - weaken + mix of negative sentences in the Critical Reasoning forum “Can you please explain what is wrong with C? Thanks” December 25, 2015 Amrabdelnaby posted a reply to Really tough CR !! in the Critical Reasoning forum “Will the payments the government will make will not affect their budget? because the payments they will make will cause an decrease in cotton production and hence an increase in prices and hence an increase in the taxes they collect as opposed to the current decreased taxes because of the current ...” December 25, 2015 Amrabdelnaby posted a reply to Number Properties - Multiples in the Data Sufficiency forum “I have a question pertaining to statement 2. I actually considered it sufficient without even doing any calculations because I applied the following rule backwards. If K is a divisor of M, and K is a divisor of N, then K is a divisor of M+N, M-N, and N-M. Now since it appears to be that ...” December 24, 2015 Amrabdelnaby posted a reply to Remainder in the Problem Solving forum “Hi Brent, I think that there is a little mistake in your calculations here: The remainder when y is divided by 12 is 3 Possible values of y = 3, 15, 28, 40, 52, ... possible values of y should be 3, 15, 27,39,51,63. etc..... You added 13 instead of 12 to 15 making you reach 28 ...” December 24, 2015 Amrabdelnaby posted a reply to Cylinder with largest volume in the Problem Solving forum “vOL OF a IS 45pi and vol of B is 75pi :)” December 24, 2015 Amrabdelnaby posted a reply to Method of argument in the Critical Reasoning forum “Definitely A” December 22, 2015 Amrabdelnaby posted a reply to Trap CR in the Critical Reasoning forum “though it is useless to people whose hearing loss stems from a neurological malfunction. This procedure will benefit a relatively small percentage of the hearing-impaired population. Notice here that the author didnt say anything about proportion of numbers between the 3 bones and neuro ...” December 22, 2015 Amrabdelnaby posted a reply to Word problem in the Problem Solving forum “Brent, I solved it using a very different approach. Please correct me if I am wrong. I did 880-440 = 440 --> the difference between the 1st and last note then to determine the 7th note: (440/12)x 6 = 660 660 is very close to 440 root 2, since root 2 is around 1.4 was i thinking right ...” December 22, 2015 Amrabdelnaby posted a reply to Advanced Quant Manhattan Question in the Problem Solving forum “Hi Brent, What''s the level of this question? I feel it is one of the top ones!” December 22, 2015 Amrabdelnaby posted a reply to Veritas Test2 Q34 in the Problem Solving forum “I had a slightly different approach here. i concluded that p/q muse be equal to 1/(599)(601) which is equal to 1/(600-1)(600+1) then p would be equal to Q/(600-1)(600+1) 1/p is the reciprocal of Q/(600-1)(600+1) which is (600-1)(600+1)/Q Hence 1/p + 1/Q = (600-1)(600+1)/Q + 1/Q which ...” December 22, 2015 Amrabdelnaby posted a new topic called intensity of different readings in the Data Sufficiency forum “Hello Pros, I realize that this is a relatively easy question; however, please let me know if my thinking process is correct On a scale that measures the intensity of a certain phenomenon, a reading of n+1 corresponds to an intensity that is 10 times the intensity corresponding to a reading of ...” December 22, 2015 Amrabdelnaby posted a reply to High School Students in the Critical Reasoning forum “It''s all about those little details and keywords that you have to catch in order to get the right answer. When taking the CR, assume that you know nothing about the real world and all the information that you need to get the right answer is only in the text you are given. If you are able to ...” December 21, 2015 Amrabdelnaby posted a new topic called Please review in the GMAT Essays (AWA) forum “Hello Pros :) Can someone please review my essay and let me know what he/she thinks? It''s my first attempt. Thanks The following appeared in the editorial section of a local newspaper: “The inflow of immigrant workers into our community has put a downward pressure on wages. In ...” December 20, 2015 Amrabdelnaby posted a reply to Tough CR: Need explanation in the Critical Reasoning forum “After giving it a second thought I totally agree with you. the passage didn''t even mention anything about talking. they mentioned passwords and stressed on physical control; hence passwords are insufficient, or else they wouldn''t have stressed on physical control. A is definitely the right ...” December 20, 2015 Amrabdelnaby posted a reply to Tough CR: Need explanation in the Critical Reasoning forum “O also think B is the right answer. I asked myself must it be true that employees dont talk about their work to anyone outside, and the answer was yes. so i chose B based on this.” December 19, 2015 Amrabdelnaby posted a reply to Assumption!!! in the Critical Reasoning forum “The assumption here is they very few overweight people eat less, so most of them gain weight again. which is A this is the assumption that the author used to conclude that obese people will gain weight again. Thinking about it, if they don''t eat more, or if more people dont eat substantially ...” December 19, 2015 Amrabdelnaby posted a new topic called decimals and fractions in the Data Sufficiency forum “0.99999999/1.0001 - 0.99999991/1.0003 = A)10^-8 b) 3(10^-8) c) 3(10^-4) D) 2(10^-4) e) 10^-4 I eliminated A & B because i figured out that the answer should yield to something to the power of -4 but i couldn''t go further with it. could you please help? Thanks” December 19, 2015 Amrabdelnaby posted a new topic called Divisible by 27? in the Problem Solving forum “Dear Pros, I figured statement one and two but can''t figure out statement three: whether the number is divisible by 27 or not. Please help. Thanks If n is a 27-digit positive integer, all of whose digits are the same, which of the following must be true? i:: n is divisible by 3 ...” December 15, 2015 Amrabdelnaby posted a new topic called Weakening the argument? in the Critical Reasoning forum “Is this a weakening the argument question? I chose answer choice A based on this understanding and it turned out to be wrong. Can someone pls explain to me the reasoning here? Thanks The Metropolitan Cooking Academy surveyed prospective students and found that students wanted a ...” December 15, 2015 Amrabdelnaby posted a new topic called Circle equationsc in the Problem Solving forum “Could you please help me with this? The standard equation of a circle is (x−h)2+(y−k)2=r2, where the point (h,k) is the center of the circle and r represents the length of the radius. If a particular circle can be represented by the equation x2+y2−8x+2y=−1, what is the radius of that ...” December 15, 2015 Amrabdelnaby posted a new topic called three distinct positive integers in the Problem Solving forum “a, b, and c are three distinct positive integers. What is the product abc? 1) a + b + c = 7 2) ab + bc + ca = 14 I understand that statement one is sufficient but i can''t work my way out in statement 2. pls help :)” December 15, 2015 Amrabdelnaby posted a reply to Annual rent in the Problem Solving forum “Thanks Matt, Your solution was very helpful. I already knew the answer to the first statement but I couldn''t figure out statement 2. so again thank you ;)” December 13, 2015 Amrabdelnaby posted a reply to An investment compounds annually at an interest rate of 34.1 in the Problem Solving forum “Brent is it possible to solve it using the formula as well?” December 10, 2015 Amrabdelnaby posted a reply to To find the fraction in the Problem Solving forum “your answer was perfect! now if you disregard the denominators of 5/4 and 1/4, you will find 1 and 5! what fraction of 5 is 1? --> 1 is one fifth of 5. so the answer is 1/5. same applies for 1/4 and 5/4... one quarter is one fifth of 5 quarters :)” December 10, 2015 Amrabdelnaby posted a new topic called Venn diagram or equations? in the Problem Solving forum “Should i solve this using venn diagram or equations or double matrix? I''m confused! Favorable Unfavorable Not Sure Candidate M 40 20 40 Candidate N 30 35 35 The table above shows the results of a survey of 100 voters who each responded ...” December 8, 2015 Amrabdelnaby posted a new topic called stamps in the Problem Solving forum “Joanna bought only 0.15$ stamps and 0.29$stamps. how many 0.15$ and 0.29$stamps did she buy? 1) she bought 4.4$ worth of stamps 2) she bought an equal number of 0.15$stamps and 0.29$ stamps”
December 8, 2015
Amrabdelnaby posted a new topic called Annual rent in the Problem Solving forum
“Guys could you please help with this? The annual rent collected by a corporation from a certain building was x percent more in 1998 than in 1997 and y percent less in 1999 than in 1998. was the annual rent collected in 1999 more than in 1997? 1) x>y 2) xy/100 < x-y”
December 8, 2015
Amrabdelnaby posted a new topic called Overlapping sets in the Problem Solving forum
“Dear All, I solved the following in 4 mintues. I did a venn diagram, broke it down to partitions, a,b,c,d,e,f,g. Created many equations and solved for g. it took so long because i created so many equations. could you please provide me with a less complicated more straight forward ...”
December 3, 2015
Amrabdelnaby posted a new topic called stocks, price per share and earnings in the Problem Solving forum
“Dear Pros, Please help with this. Last year the price per share of stock X increased by K percent and the earnings of Stock X increased by M percent, where K is greater than M. By what percent did the ratio of price per share to earnings per share increase, in terms of K & M? Can ...”
December 3, 2015
Amrabdelnaby posted a new topic called Unemployed rate in the Problem Solving forum
“In Country C, the unemployment rate among construction workers dropped from 16% on September 1, 1992 to 9% on September 1, 1996. If the number of construction workers was 20% greater on September 1, 1996, then on September 1, 1992, what was the approximate percent change in the number if unemployed ...”
November 30, 2015
Amrabdelnaby posted a reply to sum of terms in a sequence in the Problem Solving forum
“Ok I think I understand why i got it wrong now. thought that (k+1)(1/2^k) are both exponents of -1 while the fact is: -1^(k+1) x (1/2^k) hence for the first term it is -1^2 x (1/2) which is basically 1 x 1/2 = 1/2 Thanks Guru :D”
November 30, 2015
Amrabdelnaby posted a reply to y dollars from the rental venture in the Problem Solving forum
“Hello Brent, I actually solved this question using the algebra; however i see that u used it using plug ins method. I am a bit of good in both; however I want to ask you, in general, when should I use plug ins and when should i use algebra? what signs should i look for that would guide me to a ...”
November 30, 2015
Amrabdelnaby posted a reply to sum of terms in a sequence in the Problem Solving forum
“Im little bit confused regarding this question. could you please explain how did you arrive to the first few terms? also this is a negative number. i thought the outcome will be once negative and once positive. the first term for example would be -1^(k+1)(1/2)^k = -1(2)(1/2) = -1.. so how ...”
November 30, 2015
Amrabdelnaby posted a reply to Boat_upstream in the Problem Solving forum
“Hi Brent, I noticed while solving this question that it takes - if you know what you are doing - between 3-4 minutes to solve this question for V and do all the calculations. I was wondering if i encounter such a question in the assessment day if it is worthy to spend such time on it and i ...”
November 30, 2015
Amrabdelnaby posted a reply to incandescent in the Problem Solving forum
“I think it''s also possible to solve this using two unknowns.”
November 30, 2015
Amrabdelnaby posted a reply to Of the applicants passes a certain test, 15 in the Problem Solving forum
“Hi Brent, But the question says: If 20 % of the applicants who applied college X and 25% of the applicants who applied college Y applied both college X and Y so i thought that 20% of X plus 25% of Y equals to 15! why is this wrong”
November 29, 2015
Amrabdelnaby posted a reply to Probability in the Problem Solving forum
“Hi Anju, I understand the solution but i have a small question. why when choosing 5 and 15, order doesn''t matter? we can choose 5 first or 15 first so this should double the probability. for example u said it should be (2c2 x 18c3)/ 20c5 which is basically 18c3 / 20c5 well why did ...”
November 27, 2015
Amrabdelnaby posted a reply to Rain check in the Problem Solving forum
“Hi Guru, I see that you solved it by listing... is there another faster way to solve it using probability rules or combinations? please advise”
November 27, 2015
Amrabdelnaby posted a reply to At a blind taste competition a contestant is offered 3 cups in the Problem Solving forum
“Hi Guru, can you please show me how to solve it using combinations? Thanks”
November 27, 2015
Amrabdelnaby posted a reply to A single particle is accelerated through a magnetic field wh in the Problem Solving forum
“Hi GMATGuru, I am a bit confused here. if we are already testing 5 particles and the probability that right handed ones are 3/5 and the probability that left handed ones is 2/5, we already know for a fact that we have 3 right handed particles and 2 left handed particles. Hence why did we ...”
November 27, 2015
Amrabdelnaby posted a reply to 700+ Level Question in the Problem Solving forum
“Hi Brent, I am little confused about this question because my answers yield to the 60pi not 60/pi; ei: D here is how i did it; please tell me what i did wrong. case1, H=6 , R=5 since volume of a cylinder is pi x r^2 x H volume = 150pi case2: H=10, R=3 volume= 90pi Hence case ...”
November 26, 2015
Amrabdelnaby posted a reply to rectangular wooden box in the Problem Solving forum
“Vishalwin, the cylinder could be placed on one of three sides: 6x8 , 6x10 , 8x10 however you need to notice that the diameter of the cylinder will be constrained by the smaller side for example if it is placed on the side 6x8, the diameter can''t be 8, because the other dimension of the box is ...”
November 26, 2015
Amrabdelnaby posted a reply to Geometry solids in the Data Sufficiency forum
“Another way to solve it would be LW = 40 LH = 15 --> H = 15/L WH = 24 --> H = 24/W H^2 = (24x15)/(LW) = (24x15) / 40 --> by simplyfing this you get 9 Hence H equal root 9 = 3 SO LWH = 40x3 = 120 which is sufficient :D”
November 26, 2015
Amrabdelnaby posted a new topic called Geometry in the Data Sufficiency forum
“Can someone help me with this one? In triangle ABC, point X is the midpoint of side AC and point Y is the midpoint of side BC. If point R is the midpoint of line segment XC and if point S is the midpoint of line segment YC, what is the are of the triangular region RCS? 1) The area of ...”
November 26, 2015
Amrabdelnaby posted a reply to Probability: Official Prep in the Problem Solving forum
“Hi Brent, I tend to find myself solving most of the probability questions, if not all, using counting techniques. I do know that both of them are shadows of each other. I just wanted to check with you, is it actually possible to rely solely on counting to solve probability? thanks”
November 25, 2015
Amrabdelnaby posted a reply to PS_Possible Isosceles in the Data Sufficiency forum
“If this triangle was an equilateral triangle, statement one and two would have also been true. So why are they sufficient?”
November 25, 2015
Amrabdelnaby posted a reply to Wire split into circle and square in the Problem Solving forum
“Hi Brent, I had a very different approach and it led me to very different answer as well. Please tell me what i did wrong. since the wire is 40 i wrote 2 pi r = 40 r = 20/pi the area is equal to pi r^2 so pi(20/pi)^2 = 400/pi how does this answer relates to the answer choices!”
November 25, 2015
Amrabdelnaby posted a reply to NUMBERS in the Data Sufficiency forum
“Hi Brent, I actually solved it using algebra. Pls tell me if my thread of thoughts is right. Statement 1: x = 12U 12U = 8y + 12 ---> divide by 4 3U = 2y + 3 Insufficient because we have 2 unknown variables and we can''t get a common factor for them Statement 2: y = 12z x = 8(12z) ...”
November 23, 2015
Amrabdelnaby posted a reply to Is someone able to solve this OG13 problem within 2 minutes? in the Problem Solving forum
“What about 10 Brent? it might be in the middle between the maximum and minimum... why did we not consider it? Thanks”
November 23, 2015
Amrabdelnaby posted a new topic called Operations on Rational Numbers in the Problem Solving forum
“Pros, could you please help? List T consists of 30 +ve decimals, none of which is an integer, and the sum of the 30 decimals is S. The estimated sum of the 30 decimals, E, is defined as follows. Each decimal in T whose tenths digit is even is rounded up to the nearest integer and each decimal in ...”
November 22, 2015
Amrabdelnaby posted a reply to If x is a positive integer, is sqrt(x) an integer? in the Data Sufficiency forum
“Oh my! I missed that part of the question! what a shame :) I totally agree with you CEO.. if x itself is an +ve integer and √4x is also an integer then √x must be an integer because x must contain an even number of prime factors in this case, since we eliminated the possibility of x ...”
November 22, 2015
Amrabdelnaby posted a reply to If x is a positive integer, is sqrt(x) an integer? in the Data Sufficiency forum
“Brent, Question though! Now √4x is equal to 2√x, so if √x yields to 1.5 or 2.5 or 3.5 etc... √4x or 2√x will be always an integer. so how come this statement is sufficient? why did we assume that √x must be an integer if √4x is an integer although √4x =2√x”
November 22, 2015
Amrabdelnaby posted a reply to Averages and median in the Problem Solving forum
“I read your answer many times and i came to this conclusion: Because statement 1 says atleast,i tried to counter it by trying to put the numbers less than 165K in order to do so i maximized all the numbers prior to the median by making them 130 as well. So now i have we 8 houses that cost ...”
November 19, 2015
Amrabdelnaby posted a reply to In a company of only 20 employees, 10 employees make $80,000 in the Problem Solving forum “Hi Mike, Just wanted to check, what is the level of this question? Thanks” November 19, 2015 Amrabdelnaby posted a reply to An average problem in the Problem Solving forum “I think we can also do the following: sum of first 11 rounds is 11M so for the 12 rounds: (11M+90)/12 = M-5 11M+90 = 12M-60 Subtract 11M from both sides and add 60 to both sides 150 = M Hence M-5 = 150-5 = 145 BINGO!” November 19, 2015 Amrabdelnaby posted a reply to Averages and median in the Problem Solving forum “Hi Brent, Can you please explain a little further. I am very confused with this question. also what level do you think this question is?” November 19, 2015 Amrabdelnaby posted a reply to Statistics in the Problem Solving forum “Here the average distance is 2.4 or 2 5/7 of the mean so we should pic numbers that has the same average distance from the mean A has an average of 5 away from the mean B has an average of 0 away from the mean C has an average of 1 away from the mean D has an average of 2 away from the mean E ...” November 19, 2015 Amrabdelnaby posted a reply to Troubling Statistics in the Data Sufficiency forum “Hi Brent, Just to understand better, suppose that statement 1 said that set us contains only negative integers; in this case would it be sufficient?” November 19, 2015 Amrabdelnaby posted a reply to Twelve contestants at the county fair have in the Problem Solving forum “Why not 12C4?” November 18, 2015 Amrabdelnaby posted a reply to Ball Distribution in the Problem Solving forum “Hi Brent, Thank you for the answer; however I have a little question. Why did you distribute the boxes on the balls and not vice versa? I thought about distributing the balls on the boxes so i thought that we have three boxes, for the first one we can put one of 5 balls and for the ...” November 18, 2015 Amrabdelnaby posted a reply to P & C in the Problem Solving forum “Hi Guru, Can you please explain your approach here a little further. I solved it using listing and i got 150 but it took more steps and time than your method. Could you please explain a bit further to me your method. Much appreciated :)” November 18, 2015 Amrabdelnaby posted a reply to Permutations & Combinations - 6 Persons in the Problem Solving forum “Hi Brent, Thank you for the clear solution. However, I have a question. Why did we not start by the most restrictive first? and in case we do here is how i thought about it. please correct me if i am wrong. _ _ _ _ _ _ we have six places and we want to sit the most A B C 3 2 1 ...” November 18, 2015 Amrabdelnaby posted a reply to Coffee machine / SD in the Problem Solving forum “I I I I-----------------------------8.55 I I-----------------------------8.1 I I----------------------------- 7.65 I I----------------------------- Zero All what we need to do is to find the numbers between 8.55 and 7.65. so the question asked us about how many numbers are within ...” November 18, 2015 Amrabdelnaby posted a reply to Statistics in the Problem Solving forum “There''s a very easy way to do it. Consider the following: since the question asks us about the least number of withdraws and replacements we can make in order to achieve 7 marbles we will assume that every time we withdraw a marble it will be red, now we have the following ratio of red to ...” November 18, 2015 Amrabdelnaby posted a new topic called Probability question in the Problem Solving forum “Experts could you please help with this one? I know the rule of triangle: the sum of 2 sides must be greater than the third and i understand that this probability has 64 different outcomes, yet i am very confused regarding how to tackle this question. I tried complimentary as well as other rules ...” November 18, 2015 Amrabdelnaby posted a reply to probability & geometry in the Problem Solving forum “Hi Rich, So here is how i solved, yet it took from me some time. I hope you can give me an easier way/short cut to solve it. Step 1: all possible ways to choose 3 from 8 is 8C3 = 56 Step 2: break rule: I listed the 8 numbers as shown: 1 2 3 4 5 6 7 and determined that the first number has 7 ...” November 18, 2015 Amrabdelnaby posted a reply to Probability v.s combinations in the Problem Solving forum “Hi Rich, I guess I should have done the following if i wanted to do the probability rule. 1/6 x 1/5 x 2! (which is the number of ways to arrange to people) to give an answer of 1/15. Thanks Rich for the clarification :)” November 17, 2015 Amrabdelnaby posted a reply to probability and counting in the Problem Solving forum “Hi Regor, Why can''t we just do 1- (3^3/4^3) which is equal to 37/64 which is very close to 9/16” November 17, 2015 Amrabdelnaby posted a new topic called probability and counting in the Problem Solving forum “Dear all, although i solved the below probability problem in 2 different ways using probability and combinations, i was wondering if there is any way easier and shorter than mine because each time i solved it took me more than 2 minutes doing many calculations. please let me know if there is a ...” November 17, 2015 Amrabdelnaby posted a new topic called Probability in forming a triangle in the Problem Solving forum “Hello guys, Could you please help me with this? 5. The 4 sticks in a complete bag of Pick-Up Sticks are all straight-line segments of negligible width, but each has a different length: 1 inch, 2 inches, 3 inches, and 4 inches, respectively. If Tommy picks a stick at random from each of 3 ...” November 17, 2015 Amrabdelnaby posted a new topic called probability & geometry in the Problem Solving forum “Can you please help me with this? 3. If three different integers are selected at random from the integers 1 through 8, what is the probability that the three selected integers can be the side lengths of a triangle? A. 11/28 B. 27/56 C. 1/2 D. 4/7 E. 5/8” November 16, 2015 Amrabdelnaby posted a new topic called Probability v.s combinations in the Problem Solving forum “I''m little confused about something here. In the following questions my answers did not tally when i solved it using both combinations and probabii=lity methods. the question is as follows: 1. Jim and John are workers in a department that has a total of six employees. Their boss decides ...” November 16, 2015 Amrabdelnaby posted a new topic called Statistics Data Sufficiency in the Problem Solving forum “Could you please help me with this one? Beginning in January of last year, Carl made deposits of$120 into his account on the 15th of each month for several consecutive months and then made withdrawals of \$50 from the account on the 15th of each of the remaining months of last year. There were no ...”
November 16, 2015
Amrabdelnaby posted a reply to Trick Question? in the Problem Solving forum
“I concluded that the probability is half because order here doesn''t matter. isn''t B-G the same as G-B?”
November 15, 2015
Amrabdelnaby posted a reply to Trick Question? in the Problem Solving forum
“I concluded that the probability is half because order here doesn''t matter. isn''t B-G the same as G-B?”
November 15, 2015
Amrabdelnaby posted a reply to Probability questions in the Problem Solving forum
“Hi Brent, Could you please tell me whats wrong with my thinking process? P(not even or not not divisible by 3) = p(not even) = p(not even) + p (not divisble by 3) - P ( not even & not divisible by 3) p(not even) = 1/2 p(not divisible by 3) = 1/3 p(not even and not divisible by 3) = ...”
November 15, 2015
Amrabdelnaby posted a reply to Permutations & Combinations - 6 Persons in the Problem Solving forum
“Why can''t we do it in the following steps: Stage 1: we will first seat A, B & C then seat the rest: 1x1x1x3x2x1 Stage 2: then we see how many possible ways to seat A, B & C in six chairs: 6!/3! then we multiply both stages 1 & 2 together. what is wrong exactly in this ...”
November 15, 2015
Amrabdelnaby posted a new topic called Probability in the Ask the Test Maker forum
“Hi Brent, I really can''t understand the logic behind this question? Please help Smile There are 10 envelopes and 10 letters to go inside them. Each letter is menat for a specified envelope only. What is the probability that exactly 9 of them are in the right envelope? a)1/10! b)0 ...”
November 14, 2015
Amrabdelnaby posted a new topic called Counting question in the Ask the Test Maker forum
“Could you please explain the below question? :) How many different four letter words can be formed (the words need not be meaningful) using the letters of the word "MEDITERRANEAN" such that the first letter is E and the last letter is R? A. 59 B. 11! / (2!*2!*2!) C. 56 D. ...”
November 13, 2015