which of the following must be greater

Expert replies

nikhilsrl: Master | Next Rank: 500 Posts; Posts: 109; Joined: Mon Jan 10, 2011 3:05 amFollowed by: 7 members; Thanked: 8 times; GMAT Score:760

by nikhilsrl » Wed Mar 23, 2011 4:01 am

If x and y are positive, which of the following must be greater that 1/sqrt(x + y)?

I. sqrt(x + y)/2x
II. [sqrt(x) + sqrt(y)]/(x + y)
III. [sqrt(x) - sqrt(y)]/(x + y)

a) None
b) I only
c) II only
d) I and II
e) II and III

OA is D. Is there an easier to solve this than using numbers.

Like this post

Source: Beat The GMAT — Problem Solving | Wed Mar 23, 2011 4:01 am

HSPA: Legendary Member; Posts: 1101; Joined: Fri Jan 28, 2011 7:26 amFollowed by: 13 members; Thanked: 47 times; GMAT Score:640

by HSPA » Wed Mar 23, 2011 4:08 am

Let x= y = 8 => 1/sqrt(x+y) = 1/4

I) sqrt(x+y)/2x = sqrt(16)/16 = 1/4

How is OA D.. I am getting it as C

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review