Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 30 Apr 2016, 20:24

### GMAT Club Daily Prep

#### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

Author Message
Director
Joined: 12 Oct 2008
Posts: 554
Followers: 2

Kudos [?]: 267 [0], given: 2

### Show Tags

29 Oct 2009, 08:21
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statictics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Forty liters of a 60% salt solution are reduced to a 45% solution. How much must be drained off and replaced with distilled water to that the resulting solutions will contain only 45% salt?
SVP
Joined: 30 Apr 2008
Posts: 1888
Location: Oklahoma City
Schools: Hard Knocks
Followers: 39

Kudos [?]: 517 [0], given: 32

### Show Tags

29 Oct 2009, 08:52
In a mixture problem, it helps to separate out the "water" from the other element.

so with 40 liters, 60% means there are 24 liters of "salt" and 16 liters of water.

If you want to have 45% mixture when you're done, you'll have 18 liters of salt (45% of 40 = 18). So, you need to get rid of 6 liters of salt. If for every liter of mixture, you have 0.6 liters of salt, then you need to get rid of 10 liters of mixture and replace all 10 liters with water.

Forty liters of a 60% salt solution are reduced to a 45% solution. How much must be drained off and replaced with distilled water to that the resulting solutions will contain only 45% salt?

_________________

------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$. GMAT Club Premium Membership - big benefits and savings Director Joined: 12 Oct 2008 Posts: 554 Followers: 2 Kudos [?]: 267 [0], given: 2 Re: Don't have options...Please help [#permalink] ### Show Tags 29 Oct 2009, 09:02 Thanks, but how did you get this one? jallenmorris wrote: If for every liter of mixture, you have 0.6 liters of salt, then you need to get rid of 10 liters of mixture and replace all 10 liters with water. SVP Joined: 30 Apr 2008 Posts: 1888 Location: Oklahoma City Schools: Hard Knocks Followers: 39 Kudos [?]: 517 [0], given: 32 Re: Don't have options...Please help [#permalink] ### Show Tags 29 Oct 2009, 09:15 Because the mixture to start with (before draining any off and adding water) is 60% so 60% of 1 is 0.6 The way mixtures work is that the 60% represents what portion of the whole is made up of salt. So if 40 liters means that we have 24 liters of salt, and we got the number 24 by multiplying 40 x 0.6, (60% in decimal form is 0.6) then when we find out how much salt is in 1 liter, we multiply 1 x 0.6 = 0.6 salt in each. Now, we know we need less salt to go from 60% mixture to 45% mixture, but we have to figure out how much salt to get rid of, so that when we add back in water, the salt that remains is 45% of the whole solution. There are a couple of different ways to do this, figure out how much salt we have at the start (24 liters) then figure out how much we will have once we have 45% of 40 liters, whic is 18 and then the difference is 6. So if 1 liter has 0.6 liters of salt (60% of 1) then 60% of 10 = 6 liters of salt,t he difference we need to get rid of. So drain off 10 liters of mixture, and you get rid of 6 liters of salt. But now the mixture has 30 liters with 18 liters of salt. Add in 10 liters of distilled water to go back to 40 liters and we still have 18 liters of salt (we did not add any). Hope this helps. reply2spg wrote: Thanks, but how did you get this one? jallenmorris wrote: If for every liter of mixture, you have 0.6 liters of salt, then you need to get rid of 10 liters of mixture and replace all 10 liters with water. _________________ ------------------------------------ J Allen Morris **I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$.

GMAT Club Premium Membership - big benefits and savings

Display posts from previous: Sort by

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.