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 contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

20 Dec 2012, 06:23

6

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

15% (low)

Question Stats:

74% (02:12) correct
26% (01:34) wrong based on 761 sessions

HideShow timer Statistics

A tank contains 10,000 gallons of a solution that is 5 percent sodium chloride by volume. If 2,500 gallons of water evaporate from the tank, the remaining solution will be approximately what percent sodium chloride?

A tank contains 10,000 gallons of a solution that is 5 percent sodium chloride by volume. If 2,500 gallons of water evaporate from the tank, the remaining solution will be approximately what percent sodium chloride?

(A) 1.25% (B) 3.75% (C) 6.25% (D) 6.67% (E) 11.7%

"The remaining solution will be approximately what percent sodium chloride?" means: what percent of the remaining solution is sodium chloride. Now, since the remaining solution is 10,000-2,500=7,500 gallons and sodium chloride is 500 gallons (5% of initial solution of 10,000 gallons) then sodium chloride is 500/7,500*100=~6.66% of the remaining solution of 7,500 gallons.

Re: A tank contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

09 Mar 2013, 00:09

1

This post was BOOKMARKED

Walkabout wrote:

A tank contains 10,000 gallons of a solution that is 5 percent sodium chloride by volume. If 2,500 gallons of water evaporate from the tank, the remaining solution will be approximately what percent sodium chloride?

Re: A tank contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

30 Jun 2013, 21:12

I have a question.

Are we supposed to assume none of the sodium chloride was evaporated from the same original 10000 Gallons.

Hence of the 500 Gallons of original Sodium Chloride wouldn't the amount of sodium chloride in the solution also decrease by the same rate as the solution without Sodium Chloride?
_________________

Are we supposed to assume none of the sodium chloride was evaporated from the same original 10000 Gallons.

Hence of the 500 Gallons of original Sodium Chloride wouldn't the amount of sodium chloride in the solution also decrease by the same rate as the solution without Sodium Chloride?

We are told that from 10,000 gallons of a solution, evaporated 2,500 gallons of water. So, salt did not evaporate.

If it were the way you suggest (if salt evaporated at the same rate as the water) then the answer would simply be 5%.
_________________

Re: A tank contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

30 Jun 2013, 22:51

Bunuel wrote:

hfbamafan wrote:

I have a question.

Are we supposed to assume none of the sodium chloride was evaporated from the same original 10000 Gallons.

Hence of the 500 Gallons of original Sodium Chloride wouldn't the amount of sodium chloride in the solution also decrease by the same rate as the solution without Sodium Chloride?

We are told that from 10,000 gallons of a solution, evaporated 2,500 gallons of water. So, salt did not evaporate.

If it were the way you suggest (if salt evaporated at the same rate as the water) then the answer would simply be 5%.

Ok, I assumed that the two solutions were mixed in the same container.

Re: A tank contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

01 Jul 2014, 07:23

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 contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

23 Jul 2014, 09:27

Bunuel wrote:

Enael wrote:

Bunuel, even though the answer doesn't change, I still don't grasp how WATER = SOLUTION evaporated.

I have 10,000 gallons of both: NaCl and Water. 5% of NaCl = 500 gallons so water HAS to be 9,500 gallons.

It explicitly states that 2,500 gallons of water are evaporated, thus our base reduced should be 9,500 - 2,500 = 7,000 gallons of water.

So: NaCl / (NaCl+Water) = 500/(7000+500) = 1/15 = almost 7%.

As said, the answer doesn't change but the concept behind it does.

I don´t know if the problem stem were to change a bit, maybe my explanation might help.

What contradiction do you see between you solution and mine?

Just read it again, and indeed it is the same. The difference is that I separate both components first, and then subtract 2,500 from Water. You do it the other way around. It should work both ways.

As a chemical engineer, it's difficult not to follow the methodology learned over the years

Have you tried doing the math by hand? There's a pattern in the calculation that shouldn't take you too long to find; by extension, the math probably won't take you as long as you might think.

Re: A tank contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

01 Jun 2016, 08:21

Initial amount of water must be 95% of total quantity (9500 gallons); as it's given that 5% (500 gallons) is sodium chloride. lf 2500 gallons of water evaporates, remaining solution should have 7000 gallons of water and 500 gallons of sodium chloride. Then we should have something like: 500/7000, which is clearly wrong.

Initial amount of water must be 95% of total quantity (9500 gallons); as it's given that 5% (500 gallons) is sodium chloride. lf 2500 gallons of water evaporates, remaining solution should have 7000 gallons of water and 500 gallons of sodium chloride. Then we should have something like: 500/7000, which is clearly wrong.

Could someone please correct where l'm wrong?

Regards.

The remaining solution will be approximately what percent sodium chloride?

The remaining solution = 7000 gallons of water + 500 gallons of sodium chloride = 7500 gallons.

Re: A tank contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

01 Jun 2016, 11:45

ranaazad wrote:

Initial amount of water must be 95% of total quantity (9500 gallons); as it's given that 5% (500 gallons) is sodium chloride. lf 2500 gallons of water evaporates, remaining solution should have 7000 gallons of water and 500 gallons of sodium chloride. Then we should have something like: 500/7000, which is clearly wrong.

Could someone please correct where l'm wrong?

Regards.

Hope this helps -

Attachment:

Capture.PNG [ 3.75 KiB | Viewed 994 times ]

Thus the required percentage = \(\frac{500}{7500}\)x\(100\) => 6.67% _________________

Re: A tank contains 10,000 gallons of a solution that is 5 [#permalink]

Show Tags

23 Jun 2016, 09:39

Walkabout wrote:

A tank contains 10,000 gallons of a solution that is 5 percent sodium chloride by volume. If 2,500 gallons of water evaporate from the tank, the remaining solution will be approximately what percent sodium chloride?

(A) 1.25% (B) 3.75% (C) 6.25% (D) 6.67% (E) 11.7%

We start with 10,000 gallons of a solution that is 5% sodium chloride by volume. This means that there are 0.05 x 10,000 = 500 gallons of sodium chloride.

When 2,500 gallons of water evaporate we are left with 7,500 gallons of solution. From here we can determine what percent of the 7,500 gallon solution is sodium chloride.

(sodium chloride/total solution) x 100 = ?

(500/7,500) x 100 = ?

5/75 x 100 = ?

1/15 x 100 = ?

100/15 = 20/3 = 6 2/3 = 6.67%

Answer is D.
_________________

Jeffrey Miller Jeffrey Miller Head of GMAT Instruction

gmatclubot

Re: A tank contains 10,000 gallons of a solution that is 5
[#permalink]
23 Jun 2016, 09:39

Hey, guys, So, I’ve decided to run a contest in hopes of getting the word about the site out to as many applicants as possible this application season...

Whether you’re an entrepreneur, aspiring business leader, or you just think that you may want to learn more about business, the thought of getting your Masters in Business Administration...

Whether you’re an entrepreneur, aspiring business leader, or you just think that you may want to learn more about business, the thought of getting your Masters in Business Administration...