• NEW! FREE Beat The GMAT Quizzes
    NEW! FREE Beat The GMAT Quizzes
    NEW! FREE Beat The GMAT Quizzes
    Hundreds of Questions Highly Detailed Reporting Expert Explanations TAKE A FREE GMAT QUIZ
  • 7 CATs FREE!
    If you earn 100 Forum Points

    Engage in the Beat The GMAT forums to earn
    100 points for $49 worth of Veritas practice GMATs FREE

    Veritas Prep
    VERITAS PRACTICE GMAT EXAMS
    Earn 10 Points Per Post
    Earn 10 Points Per Thanks
    Earn 10 Points Per Upvote
    REDEEM NOW

mixed %

This topic has 5 member replies

mixed %

Post
X grams of water were added to the 80 grams of a strong solution of acid. As a result, the concentration of acid in the solution became 1/Y times of the initial concentration. What was the concentration of acid in the original solution?

1. X = 80
2. Y = 2

  • +1 Upvote Post
  • Quote
  • Flag
Master | Next Rank: 500 Posts Default Avatar
Joined
03 Sep 2008
Posted:
377 messages
Followed by:
2 members
Upvotes:
15
Target GMAT Score:
700+
Post
Ans is E

based on given condition we have -
let c1 be concentration

wt. of solute in the mixture = 80c1/100 gm

hence the new concentration c2 after adding X gm of water

((80c1/100) * 100) / (80+x) = c2 = c1/Y

hence we get,

80y = 80+x

From 1, we get x = 80 and y =2

but we still cant find the concentration

From 2, same as above


Hence E

  • +1 Upvote Post
  • Quote
  • Flag
Junior | Next Rank: 30 Posts Default Avatar
Joined
15 Aug 2008
Posted:
12 messages
Post
I think the OA is C. Can somebody please verify.
This is how -

Let the solution contain Z gms of Acid.
Thus concentration is Z/80

X gms water added, thus total solution = 80 + X
Thus concentration is Z/(80+X)

Z/(80+X) = (1/Y)(Z/80)

1) X = 80. Insufficient
2) Y = 2. Insufficient

Replacing both X and Y gives us the vlaue of Z. And thus can find Z/80

Answer is C

  • +1 Upvote Post
  • Quote
  • Flag
Newbie | Next Rank: 10 Posts Default Avatar
Joined
19 Jul 2008
Posted:
7 messages
Upvotes:
1
Post
lali_mew,

Z/160=Z/160 after replacing x and y.

Z can be any value, so you can't find the concentration.

IMO E

Please correct me if I'm wrong.

  • +1 Upvote Post
  • Quote
  • Flag
Legendary Member Default Avatar
Joined
22 Jul 2008
Posted:
683 messages
Followed by:
2 members
Upvotes:
73
Post
Agree with fatalmilk

The answer should be E as both the statements gives us the same information.

  • +1 Upvote Post
  • Quote
  • Flag
Junior | Next Rank: 30 Posts Default Avatar
Joined
15 Aug 2008
Posted:
12 messages
Post
You are right fatalmilk!
I overlooked that point. Both sides amount to the same.
The answer is E.
Thanks for pointing it out.

  • +1 Upvote Post
  • Quote
  • Flag
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • 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
  • 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
  • The Princeton Review
    FREE GMAT Exam
    Know how you'd score today for $0

    Available with Beat the GMAT members only code

    MORE DETAILS
    The Princeton Review
  • 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
  • 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
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh

Top First Responders*

1 Ian Stewart 53 first replies
2 Brent@GMATPrepNow 36 first replies
3 Jay@ManhattanReview 29 first replies
4 GMATGuruNY 25 first replies
5 ceilidh.erickson 15 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

Most Active Experts

1 image description Scott@TargetTestPrep

Target Test Prep

199 posts
2 image description Max@Math Revolution

Math Revolution

90 posts
3 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

76 posts
4 image description Ian Stewart

GMATiX Teacher

62 posts
5 image description GMATGuruNY

The Princeton Review Teacher

44 posts
See More Top Beat The GMAT Experts