Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

cross multiplying fractions with variables. Confused

Problem Solving — algebra and arithmetic
Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 158
Joined: Mon Nov 02, 2009 5:49 pmFollowed by: 3 members
Thanked: 2 times
by tonebeeze » Thu Apr 14, 2011 9:18 am
Hello,

I am still a little confused regarding the rules of cross-multiplying fractions that contain variables. For instance:

x/2 = 3/y vs.

x/(x-4) > 5/3

I would like some hard fast rules to cling onto, especially during the DS section when these constraints are often tested. Thanks for the help.
Top
Join the discussion
Source: — Quantitative Reasoning |
User avatar
GMAT Instructor
Posts: 1035
Joined: Fri Dec 17, 2010 11:13 amFollowed by: 365 members
Location: Los Angeles, CA
Thanked: 474 times

by VivianKerr » Thu Apr 14, 2011 12:27 pm
x/2 = 3/y

You'd multiply the numerator of one, by the denominator of the other:

(x)(y) = (2)(3)

xy = 6

When two fractions (ratios) are set equal to each other, it's called a proportion.

For x / (x - 4) > 5/3, remember that this is an inequality so it is not a proportion. We do not know what x is, so we need to be very careful when we simplify.

x / (x - 4) = x/x - x/4 = 1 - x/4

1 - x/4 > 5/3

We can continue to simplify, but remember that if we multiply or divide by a negative number, we'll need to flip the inequality.

4(1 - x/4) > 4(5/3)

4 - x > 20/3

- x > 20/3 - 4

- x > 20/3 - 12/3

- x > 8/3

x < -8/3
Vivian Kerr
GMAT Rockstar, Tutor
https://www.GMATrockstar.com
https://www.yelp.com/biz/gmat-rockstar-los-angeles

Former Kaplan and Grockit instructor, freelance GMAT content creator, now offering affordable, effective, Skype-tutoring for the GMAT at $150/hr. Contact: [email protected]

Thank you for all the "thanks" and "follows"! :-)
Top
Join the discussion