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 →

Ratio Problem

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
GMAT Instructor
Posts: 613
Joined: Thu Mar 22, 2007 6:17 amFollowed by: 64 members
Location: madrid
Thanked: 171 times
GMAT Score:790

by kevincanspain » Mon Jul 11, 2011 1:48 pm
tanyasethi wrote:If the ratio of 2 a to b is 8 times the ratio of b to a , then could be
* 1/4
* 1/2
* 2
* 1
* 4

Could someone please explain this problem to me. The answer is 1/2.
Note that the ratio of a to b can be written as a:b or a/b

Thus
2(a/b) = 8 (b/a)

2a^2 = 8b^2
a^2 = 4b^2

|a| = 2|b|

That's all I can say! Can you check the wording of the question?
Kevin Armstrong
GMAT Instructor
Gmatclasses
Madrid
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 25
Joined: Mon Jul 11, 2011 1:13 pmFollowed by: 1 member

by tanyasethi » Mon Jul 11, 2011 2:00 pm
Sorry I made a mistake typing the question, it should be then b/a could be...

the correct question is
If the ratio of 2 a to b is 8 times the ratio of b to a , then b/a could be
* 1/4
* 1/2
* 2
* 1
* 4

Sorry again! My bad! Will be more careful the next time around!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 111
Joined: Tue Dec 30, 2008 1:25 pm
Location: USA
Thanked: 28 times
GMAT Score:770

by goalevan » Mon Jul 11, 2011 2:55 pm
2a/b = 8b/a
2a^2 = 8b^2
a^2 = 4b^2
(a/b)^2 = 4
a/b = +2 or -2

Therefore 1/(a/b) = b/a could be 1/(2) or 1/(-2)

B
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 401
Joined: Tue May 24, 2011 1:14 amFollowed by: 5 members
Thanked: 37 times

by MBA.Aspirant » Tue Jul 12, 2011 2:00 am
tanyasethi wrote: If the ratio of 2 a to b is 8 times the ratio of b to a , then b/a could be
* 1/4
* 1/2
* 2
* 1
* 4
2a/b = 8b/a

2a^2 = 8b^2

a^2 = 4b^2

a = 2b

b/a = 1/2
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 25
Joined: Mon Jul 11, 2011 1:13 pmFollowed by: 1 member

by tanyasethi » Tue Jul 12, 2011 12:13 pm
Thanks a ton! :)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1