Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

A tank holds x gallons of a saltwater solution that is 20% [#permalink]

Show Tags

22 Feb 2008, 15:33

2

This post received KUDOS

10

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

65% (hard)

Question Stats:

62% (03:37) correct
38% (03:10) wrong based on 257 sessions

HideShow timer Statistics

A tank holds x gallons of a saltwater solution that is 20% salt by volume. One Fourth of the water is evaporated, leaving all of the salt. When 10 Gallons of water and 20 gallons of salt are added, the resulting mixture is 33 1/3 % salt by volume. What is the value of x?

A. 37.5 B. 75 C. 100 D. 150 E. 175

Can you show me how to solve this without backsolving, ie the real algabraic way?

Nope, 150. I can only get it by following PR's backsolving explanation. I hate that.

Original mixture has 20% salt and 80% water. Total = x Out of which Salt = 0.2x and water = 0.8x Now, 1/4 water evaporates and all salt remains. So what remains is 0.2x salt and 0.6x water. Now 20 gallons salt is added and 10 gallons of water is added. So salt now becomes -> (0.2x + 20) and water --> (0.6x+10) Amount of salt is 33.33% of total. So amount of water is 66.66%. So salt is half of the volume of water. So (0.2x+20) = (0.6x+10)/2, Solving, x = 150.

Nope, 150. I can only get it by following PR's backsolving explanation. I hate that.

Original mixture has 20% salt and 80% water. Total = x Out of which Salt = 0.2x and water = 0.8x Now, 1/4 water evaporates and all salt remains. So what remains is 0.2x salt and 0.6x water. Now 20 gallons salt is added and 10 gallons of water is added. So salt now becomes -> (0.2x + 20) and water --> (0.6x+10) Amount of salt is 33.33% of total. So amount of water is 66.66%. So salt is half of the volume of water. So (0.2x+20) = (0.6x+10)/2, Solving, x = 150.

Outstanding response. thank you. Can you describe how you started unpeeling this? I found the question wording really confusing.

Also, what level difficulty would you say this is?

Nope, 150. I can only get it by following PR's backsolving explanation. I hate that.

Original mixture has 20% salt and 80% water. Total = x Out of which Salt = 0.2x and water = 0.8x Now, 1/4 water evaporates and all salt remains. So what remains is 0.2x salt and 0.6x water. Now 20 gallons salt is added and 10 gallons of water is added. So salt now becomes -> (0.2x + 20) and water --> (0.6x+10) Amount of salt is 33.33% of total. So amount of water is 66.66%. So salt is half of the volume of water. So (0.2x+20) = (0.6x+10)/2, Solving, x = 150.

Quote:

Outstanding response. thank you. Can you describe how you started unpeeling this? I found the question wording really confusing.

Also, what level difficulty would you say this is?

Thanks. Actually , I did not solve it backwards. I solved it as per the flow given in the problem question. Honestly, I dont think this was more than a 650 level question.

Re: A tank holds x gallons of a saltwater solution that is 20% [#permalink]

Show Tags

15 Feb 2014, 16:40

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Re: A tank holds x gallons of a saltwater solution that is 20% [#permalink]

Show Tags

18 Apr 2014, 13:01

2

This post received KUDOS

1

This post was BOOKMARKED

Understand the logic of the flow of question.

Consider X initial solution.

0.2X = Salt 0.8X = Water

1/4(0.8X)= Evaporated Leaving 0.6X=water

0.6X+10=Water 0.2X+20=Salt

Salt concentration now becomes= 1/3 of the Solution

(0.2X+20)/(0.8X+30) = 1/3

X=150
_________________

Rgds, TGC! _____________________________________________________________________ I Assisted You => KUDOS Please _____________________________________________________________________________

Re: A tank holds x gallons of a saltwater solution that is 20% [#permalink]

Show Tags

27 Jun 2016, 06:12

Manbehindthecurtain wrote:

A tank holds x gallons of a saltwater solution that is 20% salt by volume. One Fourth of the water is evaporated, leaving all of the salt. When 10 Gallons of water and 20 gallons of salt are added, the resulting mixture is 33 1/3 % salt by volume. What is the value of x?

A. 37.5 B. 75 C. 100 D. 150 E. 175

Can you show me how to solve this without backsolving, ie the real algabraic way?

Got the right answer but the wording is super bad! _________________

Spread some love..Like = +1 Kudos

gmatclubot

Re: A tank holds x gallons of a saltwater solution that is 20%
[#permalink]
27 Jun 2016, 06:12

It’s quickly approaching two years since I last wrote anything on this blog. A lot has happened since then. When I last posted, I had just gotten back from...

Since my last post, I’ve got the interview decisions for the other two business schools I applied to: Denied by Wharton and Invited to Interview with Stanford. It all...

Marketing is one of those functions, that if done successfully, requires a little bit of everything. In other words, it is highly cross-functional and requires a lot of different...