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 xy does not equal zero, what is the value of xy

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |
Senior | Next Rank: 100 Posts
Posts: 94
Joined: Tue Dec 16, 2014 9:50 amFollowed by: 4 members
Location: London, UK
Thanked: 2 times
GMAT Score:770

by mbawisdom » Wed Mar 07, 2018 4:21 pm
lheiannie07 wrote:If xy does not equal zero, what is the value of xy?

(1) 2/x + 2/y = 3
(2) x^3 - (2/y)^3 = 0

What's the best way to determine the sufficient statement?

OA B
Look at statement (1) first:

2/x + 2/y = 3
(2y + 2x)/xy = 3
xy = 2(x + y)/3

We don't know x + y so we can't solve for xy --> NOT SUFFICIENT!

Look at statement (2) second:

x^3 - (2/y)^3 = 0
x^3 - 8/y^3 = 0
(xy)^3 - 8 = 0
(xy)^3 = 8
xy = 2

SUFFICIENT

Where did you get stuck?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Thu Mar 08, 2018 3:29 am
lheiannie07 wrote:If xy does not equal zero, what is the value of xy?

(1) 2/x + 2/y = 3
(2) x^3 - (2/y)^3 = 0
Statement 1: 2/x + 2/y = 3
2/x = 3 - 2/y

Case 1: y=1
Plugging y=1 into 2/x = 3 - 2/y, we get:
2/x = 3 - (2/1)
2/x = 1
2 = x
xy = 2*1 = 2.

Case 2: y=-1
Plugging y=-1 into 2/x = 3 - 2/y, we get:
2/x = 3 - (2/-1)
2/x = 5
2/5 = x
xy = (2/5)(-1) = -2/5.

Since xy can be different values, INSUFFICIENT.

Statement 2: x³ - (2/y)³ = 0
x³ = (2/y)³
x = 2/y
xy = 2.
SUFFICIENT.

The correct answer is B.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1