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: 21337

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: 1231

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: 832

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: 632

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: 1059

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: 1160

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: 632

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: 525

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: 772

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: 1299

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: 606

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: 783

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: 1059

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: 3705

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: 770