BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

If 0 < x < 1 and y > 1

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 18
Joined: Mon Nov 11, 2013 5:31 am
Thanked: 1 times
by jack0997 » Mon Jun 12, 2017 5:11 am

Timer

00:00

Answers

A

B

C

D

E

Stats

Difficulty—

If 0 < x < 1 and y > 1, [√{x + y - 2√(xy)} + √{x + y + 2√(xy)}] =

(A) √x
(B) 2√x
(C) √y + √x
(D) √y
(E) 2√y

OA E
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 amFollowed by: 34 members
Location: Grand Central / New York
Thanked: 470 times

by Jay@ManhattanReview » Mon Jun 12, 2017 5:26 am
jack0997 wrote:If 0 < x < 1 and y > 1, [√{x + y - 2√(xy)} + √{x + y + 2√(xy)}] =

(A) √x
(B) 2√x
(C) √y + √x
(D) √y
(E) 2√y

OA E
An efficient approach for such questions is by plugging in smart values for x and y.

Since we have to deal with √xy, the values chosen for x and y must be such that √xy is not an ugly number.

Say x = 1/4 and y =4. This makes √xy = √(1/4)*4 = √1 = 1. This works.

Just plug-in these values and check which option renders the correct answer.

Hope this helps!

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide

-Jay
_________________
Manhattan Review GMAT Prep

Locations: New York | Bangkok | Abu Dhabi | Rome | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 18
Joined: Mon Nov 11, 2013 5:31 am
Thanked: 1 times

by jack0997 » Tue Jun 13, 2017 12:54 am
Jay@ManhattanReview wrote:
jack0997 wrote:If 0 < x < 1 and y > 1, [√{x + y - 2√(xy)} + √{x + y + 2√(xy)}] =

(A) √x
(B) 2√x
(C) √y + √x
(D) √y
(E) 2√y

OA E
An efficient approach for such questions is by plugging in smart values for x and y.

Since we have to deal with √xy, the values chosen for x and y must be such that √xy is not an ugly number.

Say x = 1/4 and y =4. This makes √xy = √(1/4)*4 = √1 = 1. This works.

Just plug-in these values and check which option renders the correct answer.

Hope this helps!

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide

-Jay
_________________
Manhattan Review GMAT Prep

Locations: New York | Bangkok | Abu Dhabi | Rome | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Thank you, Jay. It was helpful. Could you pl. tell me the algebraic route?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 amFollowed by: 34 members
Location: Grand Central / New York
Thanked: 470 times

by Jay@ManhattanReview » Tue Jun 13, 2017 3:41 am
jack0997 wrote:
Jay@ManhattanReview wrote:
jack0997 wrote:If 0 < x < 1 and y > 1, [√{x + y - 2√(xy)} + √{x + y + 2√(xy)}] =

(A) √x
(B) 2√x
(C) √y + √x
(D) √y
(E) 2√y

OA E
An efficient approach for such questions is by plugging in smart values for x and y.

Since we have to deal with √xy, the values chosen for x and y must be such that √xy is not an ugly number.

Say x = 1/4 and y =4. This makes √xy = √(1/4)*4 = √1 = 1. This works.

Just plug-in these values and check which option renders the correct answer.

Hope this helps!

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide

-Jay
_________________
Manhattan Review GMAT Prep

Locations: New York | Bangkok | Abu Dhabi | Rome | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Thank you, Jay. It was helpful. Could you pl. tell me the algebraic route?
Well, I would not suggest you the Algebraic route; however, for the sake of your interest, here it is.

Say a = √x and b = √y

Thus,
[√{x + y - 2√(xy)} + √{x + y + 2√(xy)}] = [√{a^2 + b^2 - 2ab} + √{a^2 + b^2 + 2ab}]

= {√(a - b)^2} + {√(a + b)^2};

Since y > x, √y > √x, or b > a.

Thus, {√(a - b)^2} + {√(a + b)^2} = (b - a) + (b + a) = 2b = 2√y.

The correct answer: E

Hope this helps!

Relevant book: Manhattan Review GMAT Math Essentials Guide

-Jay
_________________
Manhattan Review GMAT Prep

Locations: New York | Mumbai | Ho Chi Minh City | Budapest | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1