It is currently 17 Oct 2017, 01:00

### 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

# Mixtures

Author Message
Senior Manager
Joined: 08 Jan 2009
Posts: 326

Kudos [?]: 176 [0], given: 5

### Show Tags

08 Sep 2009, 00:01
00:00

Difficulty:

(N/A)

Question Stats:

67% (02:39) correct 33% (03:24) wrong based on 3 sessions

### HideShow timer Statistics

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

If a portion of a half water/half alcohol mix is replaced with 25% alcohol solution, resulting in a 30% alcohol solution, what percentage of the original alcohol was replaced?

Kudos [?]: 176 [0], given: 5

Manager
Joined: 28 Jul 2009
Posts: 123

Kudos [?]: 90 [3], given: 12

Location: India
Schools: NUS, NTU, SMU, AGSM, Melbourne School of Business

### Show Tags

08 Sep 2009, 00:11
3
KUDOS
tkarthi4u wrote:
If a portion of a half water/half alcohol mix is replaced with 25% alcohol solution, resulting in a 30% alcohol solution, what percentage of the original alcohol was replaced?

Well, there are no Answer options, eh! Anyways, according to me, the answer is 80% or 4/5th of the original mix was replaced.
Using amalgamation,

50--------------25
--------30--------
5---------------20

ie : 5:20 => 1:4.

But I am not sure what "percentage of Original alcohol was replaced" means. If I did get it right, the answer for alcohol automatically comes out to be the same ie 80% or 4/5th.

What is the OA?
_________________

GMAT offended me. Now, its my turn!
Will do anything for Kudos! Please feel free to give one.

Kudos [?]: 90 [3], given: 12

Senior Manager
Joined: 08 Jan 2009
Posts: 326

Kudos [?]: 176 [0], given: 5

### Show Tags

08 Sep 2009, 18:35
Thank you. i get it. The answer is correct.

i needed to clarify one thing.

The final ratio is [ ( Concentartion of 50% alcohol mix) / ( Concentartion of 25% alcohol mix)] in the new mixture. ie 30% alcohol mixture

so to find the part replaced we are finding the amount of 25% alcohol mix in the new mixture = 4/5.

Am i correct.

Kudos [?]: 176 [0], given: 5

Manager
Joined: 10 Jul 2009
Posts: 164

Kudos [?]: 117 [0], given: 8

### Show Tags

08 Sep 2009, 20:25
As bhanushalinikhil (phew lengthy name ) mentioned the ratio 1:4 is the ratio of 50% solution to 25% solution. So four parts of 25% solution should be mixed with 1 part of 50% solution. So the replaced amount = 4/5.

Kudos [?]: 117 [0], given: 8

Senior Manager
Joined: 08 Jan 2009
Posts: 326

Kudos [?]: 176 [0], given: 5

### Show Tags

08 Sep 2009, 23:40
Thank you. Let us see the below question. I am just checking if i am getting my mixture concepts correctly.

How much water (in grams) should be added to a 35%-solution of acid to obtain a 10%-solution?There are 50 grams of the 35%-solution.

50 * 35 /100 = 17.5

17.5 / ( 50 + x) = 10 /100 1750 - 500 = 10 x so x = 125.

Is my method correct? How can do it via amalgamation?

Kudos [?]: 176 [0], given: 5

Senior Manager
Joined: 08 Jan 2009
Posts: 326

Kudos [?]: 176 [0], given: 5

### Show Tags

10 Sep 2009, 19:35
Can some help on the below question

Kudos [?]: 176 [0], given: 5

Senior Manager
Joined: 31 Aug 2009
Posts: 415

Kudos [?]: 347 [0], given: 20

Location: Sydney, Australia

### Show Tags

10 Sep 2009, 21:31
If you put all the % into the following format:

35--------------0 (since water is 0%)
--------10--------
10---------------25

That means Ratio of 35% mixture:water = 10: 25 = 2:5
If there's 50 grams of 35% mixture you need 5x25 grams of water = 125grams

Kudos [?]: 347 [0], given: 20

Re: Mixtures   [#permalink] 10 Sep 2009, 21:31
Display posts from previous: Sort by