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Two different prime numbers between 4 and 18 are chosen. When their sum is subtracted from their product, which of the following numbers could be obtained? A. 21 B. 60 C. 119 D. 180 E. 231 [spoiler]http://www.gmatmaths.com[/spoiler] All the primes in the given range -> odd Multiplication of two pri...

by anshumishra

Wed Mar 09, 2011 4:45 am
Forum: Problem Solving
Topic: prime numbers between 4 and 18
Replies: 1
Views: 4887

The longest side of a triangle is 20 and another of its side has length 10. If its area is 80, then what is the exact length of its third side? (A) √240 (B) √250 (C) √260 (D) √270 (E) √280 Made up Lets say ABC is the triangle with sides BC = 20, AB = 10, AC = ? Draw AD ⊥ BC, lets say AD...

by anshumishra

Tue Mar 08, 2011 8:07 pm
Forum: Problem Solving
Topic: its third side?
Replies: 5
Views: 1685

tonebeeze wrote:Please see problem attached.

OA = D

Can someone please show me their work. Thanks!
@x = x+1
So, (@x)^2 - @(x^2) = (x+1)^2 - (x^2+1)
= x^2 + 2x + 1 - x^2 - 1
= 2x D

by anshumishra

Tue Mar 08, 2011 6:52 pm
Forum: Problem Solving
Topic: Tricky functions problem
Replies: 2
Views: 1385

The longest side of a triangle is 20 and another of its side has length 10. If its area is 80, then what is the exact length of its third side? (A) √240 (B) √250 (C) √260 (D) √270 (E) √280 Made up Lets say ABC is the triangle with sides BC = 20, AB = 10, AC = ? Draw AD ⊥ BC, lets say AD...

by anshumishra

Tue Mar 08, 2011 4:06 am
Forum: Problem Solving
Topic: its third side?
Replies: 5
Views: 1685

@anshu, that |x-3|=<-y and y<=0 doesn't mean that we have fixed condition for |x-3|=<0 - and even if we have there are still two solutions, one is interval x<3 and the other is x=3. |x-3| <= -y and y>=0 Minimum value of |x-3| = 0 >= - y ( -y =0 only if y=0, else -y = -ve, as y has non-negative valu...

by anshumishra

Mon Mar 07, 2011 4:34 pm
Forum: Data Sufficiency
Topic: Absolute Value Question
Replies: 5
Views: 2087

What would be the solution for |X| - |Y| = |X+Y| ; XY != 0 ; X and Y are integers. Can anyone please provide algebraic method ? Here's what I did:- Squaring on both sides and using Schwarz Inequality, -2|X||Y| =< 2|XY| Therefore, 4|XY| > 0 therefore, XY > 0 ??? The answer is wrong. I am lost. Can a...

by anshumishra

Sun Mar 06, 2011 5:59 pm
Forum: GMAT Math
Topic: Absolute value question
Replies: 3
Views: 2070

From a GMAT CAT Practice Test: If y>=0, what is the value of x? I. lx-3l>=y II. lx-3l<=-y I am not sure why the correct answer is B. y>= 0, x = ? Statement 1: |x-3| >=y , clearly x can have any value based on y's value - Insufficient Statement 2: |x-3| <= -y Since mod of any value has non-negative ...

by anshumishra

Sun Mar 06, 2011 5:28 pm
Forum: Data Sufficiency
Topic: Absolute Value Question
Replies: 5
Views: 2087

Using combinatorics :
probability = # of ways to select 2 women and 2 men / # total no. of ways to select 4 persons = (3C2*5C2) / 8C4 = 3*10/70 = 3/7

by anshumishra

Sun Mar 06, 2011 3:50 pm
Forum: Problem Solving
Topic: MGMAT CAT Problem
Replies: 3
Views: 1236

If sq rt (3-2x) = sq rt (2x) + 1, then 4x^2= A. 1 B. 4 C. 2 - 2x D. 4x - 2 E. 6x - 1 Source: OG 12 OA after some discussion. √(3-2x) - √2x = 1; square both sides => 3-2x + 2x - 2√(3-2x)(2x) = 1 => 2√(3-2x)(2x) = 2 => √(3-2x)(2x) = 1; square both sides => (3-2x)*2x = 1 => 6x - 4x^2 = 1 => ...

by anshumishra

Sun Mar 06, 2011 3:40 pm
Forum: Problem Solving
Topic: If sq rt (3-2x) = sq rt (2x) + 1.....
Replies: 4
Views: 8587

Exactly like Night reader (except instead of checking the options lets find the minimum value ): p+ 1/p = k > 0 (as p> 0 , k must be greater than 0) => p^2 - kp + 1 = 0 Since, p is a real number the discriminant must be >= 0 So, D = k^2 - 4 >= 0 => k>=2 => so minimum value of k = p+1/p = 2

by anshumishra

Thu Mar 03, 2011 7:58 am
Forum: Problem Solving
Topic: Quadratic Equations
Replies: 10
Views: 2846

Tanya prepared 4 different letters to be sent to 4 different addresses. For each letter she prepared an envelope with its correct address. If the 4 letters are to be put in 4 envelopes at random, what is the probability 1. that only 1 letter will be put into the envelope with its correct address? [...

by anshumishra

Thu Mar 03, 2011 7:22 am
Forum: Problem Solving
Topic: difficult prep probability
Replies: 11
Views: 5487

Tanya prepared 4 different letters to be sent to 4 different addresses. For each letter she prepared an envelope with its correct address. If the 4 letters are to be put in 4 envelopes at random, what is the probability 1. that only 1 letter will be put into the envelope with its correct address? [...

by anshumishra

Thu Mar 03, 2011 5:04 am
Forum: Problem Solving
Topic: difficult prep probability
Replies: 11
Views: 5487

Tanya prepared 4 different letters to be sent to 4 different addresses. For each letter she prepared an envelope with its correct address. If the 4 letters are to be put in 4 envelopes at random, what is the probability 1. that only 1 letter will be put into the envelope with its correct address? [...

by anshumishra

Wed Mar 02, 2011 7:12 pm
Forum: Problem Solving
Topic: difficult prep probability
Replies: 11
Views: 5487

In how many ways can 6 identical coins be distributed among Alex, Bea and Chad? Note: Some people may receive zero coins. I don't have solution to this. Is this 28? The total number of ways of dividing n identical items among r persons, each one of whom, can receive 0,1,2 or more items(≤ n) is : ...

by anshumishra

Wed Mar 02, 2011 3:54 am
Forum: Problem Solving
Topic: Combo.
Replies: 5
Views: 1568

garuhape wrote:I'm not sure how to solve it. The explanation is very difficult. I hope that someone can give an easy one.

Image

Thanks
Should be B
Check out the solution :-
Image

by anshumishra

Tue Mar 01, 2011 3:46 pm
Forum: Problem Solving
Topic: Difficult geometry problem
Replies: 7
Views: 4749