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 →

Percent

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 116
Joined: Sat Sep 22, 2012 9:48 pm
Thanked: 3 times
by neeti2711 » Mon Oct 22, 2012 4:59 am
Forty percent of the rats included in an experiment were male rats. If some of the rats died during experiment and 30 percent of the rats that died were male rats, what was the ratio of the death rate among the male rats to the death rate among the female rats?

(A) 9/14
(B) 3/4
(C) 9/11
(D) 6/7
(E) 7/8
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: 3835
Joined: Fri Apr 02, 2010 10:00 pmFollowed by: 523 members
Location: Milpitas, CA
Thanked: 1854 times
GMAT Score:770

by Anurag@Gurome » Mon Oct 22, 2012 5:07 am
neeti2711 wrote:Forty percent of the rats included in an experiment were male rats. If some of the rats died during experiment and 30 percent of the rats that died were male rats, what was the ratio of the death rate among the male rats to the death rate among the female rats?

(A) 9/14
(B) 3/4
(C) 9/11
(D) 6/7
(E) 7/8
Algebraic Method:

Total no. of rats = R
No. of rats that died = N

No. of male rats = 40% of R = 0.4R
Death rate of male rats = 0.3N/0.4R
Death rate of female rats = 0.7N/0.6R

Therefore, ratio of the death rate among the male rats to the death rate among the female rats = (0.3N/0.4R)/(0.7N/0.6R) = 18/28 = [spoiler]9/14[/spoiler]

The correct answer is A.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 131
Joined: Wed Nov 14, 2012 2:01 pmFollowed by: 2 members
Thanked: 39 times

by puneetkhurana2000 » Mon Dec 10, 2012 12:54 pm
Died Not Died Total
Male 0.3x 40
Female 0.7x 60
Total x 100

Let us assume the total number of deaths is x, by given information male deaths is 0.3x and female will be x-0.3x = 0.7x.

There is no need to fill up second columns as we need death rate i.e. (0.3x/40)/(0.7x/60) = 9/14

Hope this helps.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 131
Joined: Wed Nov 14, 2012 2:01 pmFollowed by: 2 members
Thanked: 39 times

by puneetkhurana2000 » Mon Dec 10, 2012 12:59 pm
Sorry, the table got messed up...the numbers 40, 60 and 100 should be in last column under Total.

And 0.3x, 0.7x and x should be in first column under Died.

Second column is blank as explained in my previous post.

Hope this makes sense!!
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 » Mon Dec 10, 2012 1:49 pm
neeti2711 wrote:Forty percent of the rats included in an experiment were male rats. If some of the rats died during experiment and 30 percent of the rats that died were male rats, what was the ratio of the death rate among the male rats to the death rate among the female rats?

(A) 9/14
(B) 3/4
(C) 9/11
(D) 6/7
(E) 7/8
Let the total number of rats = 100.
Male rats = .4(100) = 40.
Thus, female rats = 100-40 = 60.

Let the total number of deaths = 10.
Male deaths = .3(10) = 3.
Thus, female deaths = 10-3 = 7.

Male death rate = (male deaths)/(total males) = 3/40.
Female death rate = (female deaths)/(total females) = 7/60.
Male death rate / female death rate = (3/40) / (7/60) = 3/40 * 60/7 = 9/14.

The correct answer is A.
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