• Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • examPAL
    Most awarded test prep in the world
    Now free for 30 days

    Available with Beat the GMAT members only code

    MORE DETAILS
    examPAL
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep

mixture problem2

This topic has 3 expert replies and 2 member replies
buoyant Master | Next Rank: 500 Posts Default Avatar
Joined
02 Mar 2013
Posted:
106 messages
Upvotes:
4

mixture problem2

Post Sun Jan 18, 2015 12:46 pm
If 12 ounces of a strong vinegar solution are diluted with 50 ounces of water to form a three-percent vinegar solution, what was the concentration of the original solution?
A) 19.3%
B) 17%
C) 16.67%
D) 15.5%
E) 12.5%

OA: D

  • +1 Upvote Post
  • Quote
  • Flag
subhakimi Newbie | Next Rank: 10 Posts Default Avatar
Joined
19 Jan 2015
Posted:
4 messages
Upvotes:
2
GMAT Score:
760
Post Mon Jan 19, 2015 9:33 am
buoyant wrote:
If 12 ounces of a strong vinegar solution are diluted with 50 ounces of water to form a three-percent vinegar solution, what was the concentration of the original solution?
A) 19.3%
B) 17%
C) 16.67%
D) 15.5%
E) 12.5%

OA: D
You can use Alligation
X____________0
.
.
......3.......
.
.
12 ..........50

So x-3/3=50/12
Or simply we can do x=3 + 50x3/2=3+12.5=15.5

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post Sun Jan 18, 2015 4:44 pm
Hi buoyant,

If you choose a "math approach", you can see that the "steps" that you have to take are essentially the same; the various explanations in this thread point that out.

This question can be set up using the Weighted Average Formula.

We're told that....
1) 12 oz of a strong solution are mixed with
2) 50 ox. of a water solution (with 0 vinegar in it)
3) The resulting mix is 3% vinegar.

We're asked for the concentration of vinegar in the 12 oz. solution.

X = % concentration in the 12 oz solution

(12(X) + 50(0)) / (12 + 50) = .03

12X + 0 = 62(.03)
12X = 1.86
X = 1.86/12

X = 186/1200
X = .155

Thus, the original solution is 15.5% vinegar.

Final Answer: D

GMAT assassins aren't born, they're made,
Rich

_________________
Contact Rich at Rich.C@empowergmat.com

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post Sun Jan 18, 2015 1:19 pm
buoyant wrote:
If 12 ounces of a strong vinegar solution are diluted with 50 ounces of water to form a three-percent vinegar solution, what was the concentration of the original solution?
A) 19.3%
B) 17%
C) 16.67%
D) 15.5%
E) 12.5%

OA: D
When 50 ounces of water is added to the 12 ounces of original solution, we get 62 ounces of a NEW solution.
The new solution is 3% vinegar.
3% of 62 = 1.86
So, the NEW solution contains 1.86 ounces of pure vinegar.
These 1.86 ounces of pure vinegar came from the ORIGINAL solution.

The ORIGINAL solution had a volume of 12 ounces. 1.86 ounces was pure vinegar.
1.86/12 = what percent?

Well, 1.8/12 = 15%, so 1.86/12 must be a little bit more than 15%.
Take D

For more on this shortcut for converting fractions to percents, see my article: http://www.gmatprepnow.com/articles/shortcut-converting-fractions-percents

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with Beat The GMAT's free 60-Day Study Guide

Check out the online reviews of our course
Come see all of our free resources

  • +1 Upvote Post
  • Quote
  • Flag
GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
Marty Murray Legendary Member
Joined
03 Feb 2014
Posted:
2050 messages
Followed by:
131 members
Upvotes:
955
GMAT Score:
800
Post Sun Jan 18, 2015 1:22 pm
buoyant wrote:
If 12 ounces of a strong vinegar solution are diluted with 50 ounces of water to form a three-percent vinegar solution, what was the concentration of the original solution?
A) 19.3%
B) 17%
C) 16.67%
D) 15.5%
E) 12.5%

OA: D
Total solution now is 12 + 50 = 62 ounces.

Total vinegar of new solution is 62 * .03 = 1.86 ounces. Since only water was added, this is also the total vinegar in the original solution.

The percentage of vinegar in the original solution is 1.86 ounces vinegar/12 ounces total solution = .155 = 15.5 percent.

Choose D.

_________________
Marty Murray
GMAT Coach
m.w.murray@hotmail.com
http://infinitemindprep.com/
In Person in the New York Area and Online Worldwide

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post Sun Jan 18, 2015 1:42 pm
buoyant wrote:
If 12 ounces of a strong vinegar solution are diluted with 50 ounces of water to form a three-percent vinegar solution, what was the concentration of the original solution?
A) 19.3%
B) 17%
C) 16.67%
D) 15.5%
E) 12.5%
Alternate approach:

12 ounces of a solution that is x% vinegar are combined with 50 ounces of water that is 0% vinegar to yield a 62-ounce solution that is 3% vinegar:
12x + 50*0 = 62*3
12x = 186
x = 186/12 = 31/2 = 15.5.

The correct answer is D.

_________________
Mitch Hunt
GMAT Private Tutor
GMATGuruNY@gmail.com
If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon.
Available for tutoring in NYC and long-distance.
For more information, please email me at GMATGuruNY@gmail.com.

  • +1 Upvote Post
  • Quote
  • Flag
Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.

Best Conversation Starters

1 lheiannie07 108 topics
2 ardz24 67 topics
3 Roland2rule 63 topics
4 LUANDATO 50 topics
5 swerve 43 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description GMATGuruNY

The Princeton Review Teacher

152 posts
2 image description Jeff@TargetTestPrep

Target Test Prep

106 posts
3 image description Rich.C@EMPOWERgma...

EMPOWERgmat

103 posts
4 image description Scott@TargetTestPrep

Target Test Prep

96 posts
5 image description Max@Math Revolution

Math Revolution

86 posts
See More Top Beat The GMAT Experts