Two different solutions of alcohol with respective proportio : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 21 Jan 2017, 01:10

### 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

# Two different solutions of alcohol with respective proportio

Author Message
TAGS:

### Hide Tags

Director
Joined: 25 Oct 2008
Posts: 608
Location: Kolkata,India
Followers: 13

Kudos [?]: 798 [0], given: 100

Two different solutions of alcohol with respective proportio [#permalink]

### Show Tags

13 Aug 2009, 15:12
9
This post was
BOOKMARKED
00:00

Difficulty:

(N/A)

Question Stats:

79% (03:01) correct 21% (01:43) wrong based on 20 sessions

### HideShow timer Statistics

Two different solutions of alcohol with respective proportions of alcohol to water of 3:1 and 2:3 were combined. What is the concentration of alcohol in the new solution if the first solution was 4 times the amount of the second solution?
_________________

http://gmatclub.com/forum/countdown-beginshas-ended-85483-40.html#p649902

Manager
Joined: 25 Jul 2009
Posts: 116
Schools: NYU, NUS, ISB, DUKE, ROSS, DARDEN
Followers: 5

Kudos [?]: 229 [6] , given: 17

Re: Two different solutions of alcohol [#permalink]

### Show Tags

13 Aug 2009, 15:19
6
KUDOS
1
This post was
BOOKMARKED
tejal777 wrote:
Two different solutions of alcohol with respective proportions of alcohol to water of 3:1 and 2:3 were combined. What is the concentration of alcohol in the new solution if the first solution was 4 times the amount of the second solution?

SOL:
Lets assume that 40L of sol1 was mixed with 10L of sol2.

Alcohol in Sol1: 40*3/4 = 30L
Alcohol in Sol2: 10*2/5 = 4L

Total Alcohol in the mixed solution of 50L = 30 + 4 = 34L

Alcohol concentration in the new sol: (34/50)*100 = 68%
_________________

KUDOS me if I deserve it !!

My GMAT Debrief - 740 (Q50, V39) | My Test-Taking Strategies for GMAT | Sameer's SC Notes

Director
Joined: 25 Oct 2008
Posts: 608
Location: Kolkata,India
Followers: 13

Kudos [?]: 798 [0], given: 100

Re: Two different solutions of alcohol [#permalink]

### Show Tags

14 Aug 2009, 16:51
Thank you.It's perfect!
_________________

http://gmatclub.com/forum/countdown-beginshas-ended-85483-40.html#p649902

Director
Joined: 01 Apr 2008
Posts: 897
Name: Ronak Amin
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 28

Kudos [?]: 645 [0], given: 18

Re: Two different solutions of alcohol [#permalink]

### Show Tags

15 Aug 2009, 02:35
Good strategy by samrus. A slightly different way using variables:

Let sol1 have x liters, and sol2 have y liters.
The ratio of alcohol to water in the final solution will be :
[ (3/4)*x + (2/5)*y ] / [ (1/4)*x + (3/5)*y ]

Now, x=4y, substituting x in the above ratio, we get 17/8 as the ratio of alcohol to water in the final solution.
Hence, concentration of alcohol is (17/25)*100 % = 68%
Intern
Joined: 10 Nov 2009
Posts: 5
Followers: 0

Kudos [?]: 1 [1] , given: 1

Re: Two different solutions of alcohol [#permalink]

### Show Tags

04 Feb 2010, 18:40
1
KUDOS
I have one more way of doing this with the grid

Assume 40 Liters for sol 1 and 10 Liters for sol 2

Liters.....%.......Totals
40........75%....40(.75)
10........40%......10(.40)
50.........X........

So you have 50X=40(.75)+10(.40)
50x=30+4
50x=34
x=.68 or 68%
Intern
Joined: 27 Jan 2010
Posts: 30
Followers: 0

Kudos [?]: 7 [0], given: 0

Re: Two different solutions of alcohol [#permalink]

### Show Tags

16 Apr 2010, 14:30
Solution B Let it be X
Ratio - 2:3
2y+3Y=X
5y=X
so y=X/5
Now ratio converted to amount becomes 2X/5 and 3X/5

Solution A will be 4X
Ratio - 3:1
3y+1y=4X
y=X
Ratio converted to amount = 3X and 1X

Mixture (A+B) Amount = 3x+1x = 4x
Alcohol amount = 3X+ 2X/5 -----------------------FROM ABOVE
= 17X/5

Concentration = individual amount /total amount *100 = 17x/5 * 1/5x *100 = 17/25*100 = 68%
Intern
Joined: 07 Apr 2010
Posts: 23
Followers: 1

Kudos [?]: 9 [0], given: 32

Re: Two different solutions of alcohol [#permalink]

### Show Tags

16 Apr 2010, 16:36
A different approach:
Alcohol in soln1 = 3/4 and in soln2 = 2/5
Using Alligation:
3/4--------?--2/5
4 : 1
So the resultant ratio (the ?) is at a 1/5th distance from 3/4 (or conversely at a 4/5th distance from 2/5.
3/4 - 2/5 = 7/20
Now, calculating 1/5th of 7/20 and subtracting it from 3/4
(3/4) - (1*5)/(7*20)
= 75/100 - 7/100
= 68/100
= 68%

This approach is not quite advisable in this particular problem unless one is instinctive wrt alligation, but definitely awfully handy in other scenarios. This is just to enlighten people towards proper understanding of Alligation
_________________

In a Normal Distribution, only the Average 'Stand Out'

Director
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 651
Followers: 42

Kudos [?]: 863 [3] , given: 39

Re: Two different solutions of alcohol [#permalink]

### Show Tags

11 Dec 2011, 09:57
3
KUDOS
Second solution = 20
Thus first solution = 80
New solution (20+80) = 100

Alcohol in first solution = 80*3/4 = 60
Alcohol in second solution = 20*2/5 = 8
Total Alcohol = 68
Concentration of Alcohol 68/100*100= 68% Ans.
_________________

Collections:-
PSof OG solved by GC members: http://gmatclub.com/forum/collection-ps-with-solution-from-gmatclub-110005.html
DS of OG solved by GC members: http://gmatclub.com/forum/collection-ds-with-solution-from-gmatclub-110004.html
100 GMAT PREP Quantitative collection http://gmatclub.com/forum/gmat-prep-problem-collections-114358.html
Collections of work/rate problems with solutions http://gmatclub.com/forum/collections-of-work-rate-problem-with-solutions-118919.html
Mixture problems in a file with best solutions: http://gmatclub.com/forum/mixture-problems-with-best-and-easy-solutions-all-together-124644.html

Manager
Joined: 26 Apr 2011
Posts: 228
Followers: 2

Kudos [?]: 2 [0], given: 14

Re: Two different solutions of alcohol [#permalink]

### Show Tags

11 Dec 2011, 22:08
perfect explained by samrus98
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13471
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: Two different solutions of alcohol [#permalink]

### Show Tags

01 Jun 2014, 23:11
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.
_________________
Manager
Status: folding sleeves up
Joined: 26 Apr 2013
Posts: 157
Location: India
Concentration: Finance, Strategy
GMAT 1: 530 Q39 V23
GMAT 2: 560 Q42 V26
GPA: 3.5
WE: Consulting (Computer Hardware)
Followers: 1

Kudos [?]: 85 [0], given: 39

Re: Two different solutions of alcohol with respective proportio [#permalink]

### Show Tags

10 Sep 2014, 13:11
tejal777 wrote:
Two different solutions of alcohol with respective proportions of alcohol to water of 3:1 and 2:3 were combined. What is the concentration of alcohol in the new solution if the first solution was 4 times the amount of the second solution?

(x-(2/5))/((3/4)-x) = 4/1

5x=2/5+3

x=17/25

%= 68%
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13471
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: Two different solutions of alcohol with respective proportio [#permalink]

### Show Tags

01 Sep 2016, 04:05
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.
_________________
Senior Manager
Joined: 07 Dec 2014
Posts: 491
Followers: 3

Kudos [?]: 82 [0], given: 2

Two different solutions of alcohol with respective proportio [#permalink]

### Show Tags

01 Sep 2016, 09:10
Two different solutions of alcohol with respective proportions of alcohol to water of 3:1 and 2:3 were combined. What is the concentration of alcohol in the new solution if the first solution was 4 times the amount of the second solution?

let x=% of alcohol in new solution
3/4*4+2/5=5x
x=68%
Intern
Joined: 14 May 2014
Posts: 7
Followers: 0

Kudos [?]: 8 [2] , given: 5

Re: Two different solutions of alcohol with respective proportio [#permalink]

### Show Tags

11 Sep 2016, 22:55
2
KUDOS
Can someone help to explain why solving the question as below didnt give OA?
x: the proportion of alcohol to water of new solution
(x-2/3)/(3-x)=4
15x=38
x=38/15
=>> the concentration of alcohol in the new solution is 38/(38+15)=38/53??

Re: Two different solutions of alcohol with respective proportio   [#permalink] 11 Sep 2016, 22:55
Similar topics Replies Last post
Similar
Topics:
24 Solution X is 10 percent alcohol by volume, and solution Y is 30 perce 11 23 Mar 2015, 05:45
3 If two different solutions of alcohol with a respective proportion of 4 28 Feb 2015, 23:52
17 10% of a 50% alcohol solution is replaced with water 11 25 Oct 2014, 21:53
14 If two different solutions of alcohol with a respective prop 15 20 Aug 2010, 22:55
5 A 50-liter solution of alcohol and water is 5 percent alcohol. If 1.5 8 24 Nov 2007, 01:18
Display posts from previous: Sort by