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

Redeem

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.

★★★★★5.0559 reviews
GMATLiveTeach Starts Oct 17
Chris Peckover, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Chris Peckover, 100th-Percentile GMAT Scorer

Oct 17 · Chris Peckover
Sat · 11:00 AM to 2:00 PM ET
Oct 20 · Chris Peckover
Tue, Thu · 8:00 to 10:00 PM ET
Oct 25 · Josh Braslow
Sun · 1:00 to 4:00 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
EALiveTeachOnDemand 5 seats left Start anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Sun · 9:30 AM to 12:30 PM ET
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
GMATOnDemand Start 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 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

Mixture problem

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 243
Joined: Sun Jul 12, 2009 7:12 amFollowed by: 2 members
Location: Dominican Republic
Thanked: 31 times
GMAT Score:480

by MAAJ » Wed Apr 27, 2011 3:47 pm
nadib002 wrote:A car's radiator has 24 quarts of a 40% antifreeze solution. How many quarts should be drained and replaced with pure antifreeze if the final mixture is to be 50% antifreeze.
24 * 0.4 = 9.6

(9.6 + x)/24 = 0.5
9.6 + x = 12
x = 12 - 9.6
x = 2.4
"There's a difference between interest and commitment. When you're interested in doing something, you do it only when circumstance permit. When you're committed to something, you accept no excuses, only results."
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 41
Joined: Mon Mar 02, 2009 6:27 pm

by nadib002 » Wed Apr 27, 2011 7:24 pm
Experts could you please reply
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 423
Joined: Fri Jun 11, 2010 7:59 amFollowed by: 2 members
Location: Seattle, WA
Thanked: 86 times

by srcc25anu » Wed Apr 27, 2011 10:53 pm
can solve it using allegation

40% - - - 100%
- - 50% - -
5:1 ratio for 40% antifreeze and 100% antifreeze

since 40% antifreeze = 24 quarts or 5x=24 therefore 1x = 24/5 = 4.8 quarts of 100% antifreeze should be added
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 79
Joined: Mon Sep 15, 2008 5:54 pm
Thanked: 3 times

by DarkKnight » Thu Apr 28, 2011 6:04 am
I agree with MAAJ's solution.

x=2.4

Whats the OA?
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 Apr 28, 2011 6:53 am
nadib002 wrote:A car's radiator has 24 quarts of a 40% antifreeze solution. How many quarts should be drained and replaced with pure antifreeze if the final mixture is to be 50% antifreeze.
We could plug in the answers.
Since 50% of the final mixture must be antifreeze, the correct answer will yield .5*24 = 12 quarts of antifreeze.
One of the answers would say that 4 quarts of the solution should be replaced with pure antifreeze.

Answer choice: 4 quarts of pure antifreeze.
Antifreeze in remaining 20 quarts = .4*20 = 8.
Total antifreeze = 8+4 = 12.

The correct answer is 4 quarts.
Last edited by GMATGuruNY on Thu Apr 28, 2011 7:48 am, edited 1 time in total.
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
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 Apr 28, 2011 6:59 am
srcc25anu wrote:can solve it using allegation

40% - - - 100%
- - 50% - -
5:1 ratio for 40% antifreeze and 100% antifreeze

since 40% antifreeze = 24 quarts or 5x=24 therefore 1x = 24/5 = 4.8 quarts of 100% antifreeze should be added
Alligation is a great approach for mixture problems, but be careful: you determined the correct ratio of solution:antifreeze but not the correct amount of pure antifreeze that is needed.

The total volume must remain 24 quarts.
Given that the ratio of solution:antifreeze is 5:1, since 5+1 = 6, the pure antifreeze must be 1/6 of the 24 quarts.
Pure antifreeze = (1/6)*24 = 4.

This sort of error is easily avoided if you plug in the answers, as I suggested in my post above.
Last edited by GMATGuruNY on Thu Apr 28, 2011 8:37 am, edited 1 time in total.
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
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 Apr 28, 2011 7:16 am
MAAJ wrote:
nadib002 wrote:A car's radiator has 24 quarts of a 40% antifreeze solution. How many quarts should be drained and replaced with pure antifreeze if the final mixture is to be 50% antifreeze.
24 * 0.4 = 9.6

(9.6 + x)/24 = 0.5
9.6 + x = 12
x = 12 - 9.6
x = 2.4
If you want to solve algebraically, here's one approach:

Let x = pure antifreeze.
Remaining solution = 24-x.
Antifreeze in remaining solution = .4(24-x).
Desired amount of antifreeze in final mixture = .5*24 = 12.

Thus:
x + .4(24-x) = 12.
x + 9.6 - .4x = 12.
10x + 96 - 4x = 120.
6x = 24.
x = 4.

I find plugging in the answers much easier -- and safer. When you use algebra, you can easily make an error. When you plug in the answers, it is virtually impossible not to determine the OA, because you're proving that the answer choice is correct.
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
User avatar
Master | Next Rank: 500 Posts
Posts: 243
Joined: Sun Jul 12, 2009 7:12 amFollowed by: 2 members
Location: Dominican Republic
Thanked: 31 times
GMAT Score:480

by MAAJ » Thu Apr 28, 2011 7:42 am
:o!!! missed the word quarts! my bad!
GMATGuruNY wrote:
nadib002 wrote:A car's radiator has 24 quarts of a 40% antifreeze solution. How many quarts should be drained and replaced with pure antifreeze if the final mixture is to be 50% antifreeze.
We could plug in the answers, one of which would say that 4 quarts of the solution should be replaced with pure antifreeze.

Answer choice: 4 quarts.
Antifreeze in remaining 20 quarts = .4*20 = 8.
Total antifreeze = 8+4 = 12.
Antifreeze/Total Solution = 12/24 = 50%.

The correct answer is 4 quarts.
"There's a difference between interest and commitment. When you're interested in doing something, you do it only when circumstance permit. When you're committed to something, you accept no excuses, only results."
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 41
Joined: Mon Mar 02, 2009 6:27 pm

by nadib002 » Thu Apr 28, 2011 8:37 am
thanks everyone for responding

The correct answer is "4"
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1