Search found 59 matches
The solution on MGMAT states "No consecutive integers share the same prime factors".
In fact, can I also say "No consecutive integers share the same factor, irregardless if its prime or non prime, except 1" ?
Can someone confirm?
- by valleeny
Sat Dec 26, 2009 11:48 pm- Forum: Problem Solving
- Topic: tough prime factor... GMAT Prep Test
- Replies: 9
- Views: 12528
Hi rockeyb, This is a basic concept of percentages. Say, if you add x% of a certain value onto that value to get y. Taking x% of y off from y will not get you back to the original value. Try it with an example. Say 20% of 100. If you add 20% to 100 you get 120. On the other hand, 20% of 120 is 24. I...
- by valleeny
Sat Dec 26, 2009 11:18 pm- Forum: Problem Solving
- Topic: OG #12 PS #123
- Replies: 3
- Views: 2097
Hi
I always ended up using algebra for most problems.
In the initial solution, there is 1 gallon of ethanol and 19 gallons of gasoline.
Let the amount of ethanol added = x
So the solution becomes
(0.1)(20+x) + 19 = 20 + x
Solve for x = 10/9
- by valleeny
Sat Dec 26, 2009 11:09 pm- Forum: Problem Solving
- Topic: Mixture
- Replies: 6
- Views: 2852
- by valleeny
Sat Dec 26, 2009 10:30 pm- Forum: Problem Solving
- Topic: Participant
- Replies: 4
- Views: 6937
- by valleeny
Sat Dec 26, 2009 10:25 pm- Forum: Problem Solving
- Topic: GMAT Math preperation
- Replies: 4
- Views: 1670
I cannot readily see this concept in a blink when it comes to this kind of question. Is there a concept or explanation that I have to understand for this?durgesh79 wrote: for x to be min, all other will have the same population equal to 1.1x
- by valleeny
Sat Dec 26, 2009 10:01 pm- Forum: Problem Solving
- Topic: GMAT PREP Question (Population)
- Replies: 23
- Views: 11605
What am I missing in understanding this question? I thought the question is asking for the smallest factor not the biggest? So the smallest prime factor of h(100) is 2? I don't understand.
- by valleeny
Wed Dec 23, 2009 11:57 pm- Forum: Problem Solving
- Topic: The smallest prime factor of h(100) + 1
- Replies: 7
- Views: 21147
Hi pink_08 for the sequence you gave, to find even numbers in that sequence you have to redefine the set. So for your example it's redefined to 2,3,4,5,6,7,8 essentially. So using the formula you will still get 4 even numbers.
- by valleeny
Wed Dec 23, 2009 10:06 pm- Forum: GMAT Math
- Topic: sum of all even numbers from 99 to 301
- Replies: 19
- Views: 80437
Hi Testluv
The problem becomes more complicated if thr probability of raining is not equal to the probability of not raining = 1/2. In this case I don't think you can simply use (total desired events/total possible outcomes)?
- by valleeny
Tue Dec 22, 2009 8:34 pm- Forum: Problem Solving
- Topic: Probability Problem - Cumbersome Solution
- Replies: 17
- Views: 11786
Hi Testluv
The problem becomes more complicated if thr probability of raining is not equal to the probability of not raining = 1/2. In this case I don't think you can simply use (total desired events/total possible outcomes)?
- by valleeny
Tue Dec 22, 2009 8:02 pm- Forum: Problem Solving
- Topic: Probability Problem - Cumbersome Solution
- Replies: 17
- Views: 11786
Essentially the logic for Testluv's formula is this.
Probability of rain or no rain on a given day =1/2
Probability of ANY combination of 3 days of rain out of 5 = (1/2)^3 * (1/2)^2 = 1/32
No. of ways to have 3 days rain out of 5 = 5C3 = 10
Total probabilty = 10 * 1/32
- by valleeny
Mon Dec 21, 2009 4:34 pm- Forum: Problem Solving
- Topic: Probability Problem - Cumbersome Solution
- Replies: 17
- Views: 11786
- by valleeny
Mon Dec 21, 2009 4:12 pm- Forum: Problem Solving
- Topic: 2 of the 4 expressions
- Replies: 3
- Views: 1329
Inequality question
Is x + y > 0 ? (I) x² - y² > 1 (II) x/y + 1 > 0 (A) Statement (I) ALONE is sufficient, but statement (II) alone is not sufficient (B) Statement (II) ALONE is sufficient, but statement (I) is not sufficient (C) BOTH statements TOGETHER are sufficient, but NEITHER statement alone is sufficient (D) E...
- by valleeny
Wed Dec 16, 2009 1:18 am- Forum: Data Sufficiency
- Topic: Inequality question
- Replies: 2
- Views: 1447
I spent hours and managed to convince myself of all concept spoken here and I am replying here to drill the concept so that such questions will never be an issue again. 1) For any given set of numbers, first we need to redefine the range that the question is asking for. Eg. Sum of all even numbers f...
- by valleeny
Tue Dec 15, 2009 11:20 pm- Forum: GMAT Math
- Topic: sum of all even numbers from 99 to 301
- Replies: 19
- Views: 80437
Is the ans D? I don't know of a short method either. I had to insert numbers and see the pattern. Not good. Maybe you can share your method.
- by valleeny
Mon Dec 14, 2009 4:37 pm- Forum: Problem Solving
- Topic: Faster way to solve this.
- Replies: 3
- Views: 1232