Search found 143 matches
Is n odd ? 1. a^n – b^n is divisible by a – b 2. a^n + b^n is not divisible by a + b (1) a^n - b^n is divisible by a - b This works for n = 1 -> a-b mod a-b = 0 This also works for any even n >= 2 -> a^2-b^2 -> (a-b)(a+b) mod (a-b) = 0 INSUFF (2) a^n + b^n is NOT divisible by a+b SUFF B Can som...
- by krusta80
Fri Apr 06, 2012 2:56 am- Forum: Data Sufficiency
- Topic: DS + nth power
- Replies: 58
- Views: 23905
can someone please review this question and more specifically - the way i did it. i need confirmation that i solved the problem correctly. i know there are many many ways of solving rate problems; with respect - @ this point it's too late for me to learn new ways - just hoping an expert can follow ...
- by krusta80
Sat Mar 17, 2012 6:32 am- Forum: Problem Solving
- Topic: need confirmation that this question was done correctly pls
- Replies: 3
- Views: 1618
If t = s - 3, what is s + t? Answer the question as ODD, EVEN or CANNOT BE DETERMINED Source: Manhattan GMAT Number Properties Strategy Guide, q. 12, pg. 33 OA: ODD First off, I'm assuming that the question states that s and t are integers? With that assumption in mind, his question is testing your...
- by krusta80
Sat Mar 17, 2012 6:04 am- Forum: Problem Solving
- Topic: Number properties question- MGMAT Guide
- Replies: 7
- Views: 1304
Thanks for the explanation. Please let me know why you multiplied [root x - root ( x + y)] / [root x - root (x + y)] to get rid of the denominator, instead of multiplying the equation by [root x + root ( x + y)] / [root x + root ( x + y)]? Shouldn't the denominator and numerator be multiplied by th...
- by krusta80
Wed Mar 07, 2012 7:05 pm- Forum: Problem Solving
- Topic: Roots problem
- Replies: 3
- Views: 969
product(evens from 2 through n) = 2^(n/2) * (n/2)! for n = 100, product = 2^50 * 50! So, we need to find the smallest prime factor of 2^50 * 50! + 1 Now the key to this question starts to present itself: 50! is a multiple of all prime numbers less than 50, since 50! is the product of ALL integers fr...
- by krusta80
Wed Mar 07, 2012 7:23 am- Forum: Problem Solving
- Topic: H(100) + 1
- Replies: 3
- Views: 1419
Q baseball world series matches 2 teams against each other in best of seven series.The first team to win four games wins the series and no subsequent games are played.If you have no special information about either of two teams,what is probability that world series will consist of fewer than 7 game...
- by krusta80
Wed Mar 07, 2012 7:14 am- Forum: Problem Solving
- Topic: important gmat probability problem plz help
- Replies: 3
- Views: 1541
If x > 0 and y > 0, which of the following is equal to 1/(root x + root (x + y))? (A) 1/y (B) Root (2x + y) (C) Root x/Root(x + y) (D) (Root x - Root (x + y))/y (E) (Root (x + y) - Root x)/y OA: E 1/[root (x) + root (x + y)] = ? Let's try to remove the roots from the denominator by multiplying by [...
- by krusta80
Tue Mar 06, 2012 7:12 pm- Forum: Problem Solving
- Topic: Roots problem
- Replies: 3
- Views: 969
If z is a positive integer, is root z an integer? 1. Root (xz) is an integer 2. x = z^3 OA: E Part 1: sqrt(xz) is an integer Examples make this easy... x = 1 AND z = 4. sqrt(4) = 2 x = 2 and z = 2. sqrt(2) NOT an integer INSUFFICIENT Part 2: x = z^3 This puts no restrictions on z. INSUFFICIENT (1) ...
- by krusta80
Tue Mar 06, 2012 6:37 pm- Forum: Data Sufficiency
- Topic: Roots problem
- Replies: 2
- Views: 806
A large rectangular box is 4 feet wide, 5 feet long, and 8 feet tall. A metal cylinder is to be fitted snugly into the box and stood upright on its base, resting on any one of the 6 sides of the box. Of all such cylinders that could fit into the box, what is the diameter, in feet, of the one that h...
- by krusta80
Tue Mar 06, 2012 6:17 pm- Forum: Problem Solving
- Topic: Cylinder in a rectangle
- Replies: 3
- Views: 1156
Victor's job requires him to complete a series of identical jobs. If vitor is supervised at work, he finishes each job three days faster than if he is unsupervised. If Victor works for 144 days and is supervised for half the time, he will finish 36 jobs. How long would it take Victor to complete 10...
- by krusta80
Tue Mar 06, 2012 6:04 pm- Forum: Problem Solving
- Topic: Rate/Work
- Replies: 6
- Views: 1822
Every positive even integer n, the function h(n) is defined to be 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 30 D between 30 and 40 E greater than 40 Can somebody explain thi...
- by krusta80
Tue Mar 06, 2012 5:41 pm- Forum: Problem Solving
- Topic: H(100) + 1
- Replies: 2
- Views: 977
Line q is defined by the equation y = mx + b, where m < 0. Does line q pass through (5,4)? (1) When it is reflected around the x-axis, line q passes through (3,-4) (2) When it is reflected around the y-axis, line q passes through (-5,3) [spoiler]OA: D Source: Grockit[/spoiler] m < 0 Plugging in 5 f...
- by krusta80
Mon Mar 05, 2012 10:07 pm- Forum: Data Sufficiency
- Topic: Reflection of line
- Replies: 2
- Views: 1112
When positive integer X is divided by positive integer Y, the remainder is 9. If X/Y = 96.12, what is the value of Y? (A) 96 (B) 75 (C) 48 (D) 25 (E) 12 Ok - I don't remember the secret my princeton review teacher, Brian taught us on how to do these. I do remember a little nugget of esoterica taugh...
- by krusta80
Mon Mar 05, 2012 9:50 pm- Forum: Problem Solving
- Topic: OG PS 106
- Replies: 6
- Views: 1419
Thanks again for all of your help. I had my GMAT today and while I didn't get my target score of 700, I came reasonably close. Your tips helped me on multiple quant questions significantly. I will more than likely retake it soon, so I'll be sure to get back in touch with you on some of these number...
- by krusta80
Mon Mar 05, 2012 6:42 pm- Forum: GMAT Math
- Topic: Number properties help needed
- Replies: 15
- Views: 4607
noticing that neo and krusta got the same end result (C) but used slightly different formulas in order to work them. only reason i'm asking is because the numbers end up different; is there a right or wrong way to get this? meaning, did one of these way accidentally lead to the correct answer where...
- by krusta80
Mon Mar 05, 2012 6:35 pm- Forum: Problem Solving
- Topic: Is it the wording?
- Replies: 5
- Views: 1172