water measures 60

This topic has expert replies
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

water measures 60

by sanju09 » Sat May 08, 2010 6:16 am
A mixture of milk and water measures 60 liters. It contains 20 percent water. How many liters of water should be added to it so that water in the resulting mixture may be 25 percent?
(A) 4
(B) 5
(C) 6
(D) 8
(E) 10
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Source: — Problem Solving |

User avatar
Legendary Member
Posts: 1022
Joined: Mon Jul 20, 2009 11:49 pm
Location: Gandhinagar
Thanked: 41 times
Followed by:2 members

by shashank.ism » Sat May 08, 2010 6:38 am
sanju09 wrote:A mixture of milk and water measures 60 liters. It contains 20 percent water. How many liters of water should be added to it so that water in the resulting mixture may be 25 percent?
(A) 4
(B) 5
(C) 6
(D) 8
(E) 10
total amount of mix= 60 liters
amount of water = 0.20 x 60 = 12 liters
Let X liters amount of water be added .
so (X+ 12) / (X+60) = 0.25
--> X+ 12 = 0.25 X + 15 --> 0.75 X = 3-->[spoiler] X = 3/0.75 = 4 Ans A[/spoiler]
My Websites:
www.mba.webmaggu.com - India's social Network for MBA Aspirants

www.deal.webmaggu.com -India's online discount, coupon, free stuff informer.

www.dictionary.webmaggu.com - A compact free online dictionary with images.

Nothing is Impossible, even Impossible says I'm possible.

User avatar
Legendary Member
Posts: 526
Joined: Sat Feb 21, 2009 11:47 pm
Location: India
Thanked: 68 times
GMAT Score:680

by harshavardhanc » Sat May 08, 2010 6:50 am
sanju09 wrote:A mixture of milk and water measures 60 liters. It contains 20 percent water. How many liters of water should be added to it so that water in the resulting mixture may be 25 percent?
(A) 4
(B) 5
(C) 6
(D) 8
(E) 10
two ways to solve this problem :

first, considering the water quantity.


the water in the solution is 12 lts, so (12+x)/(60+x) = 1/4

4x + 48 = 60 + x

x = 4 lts

second, if you consider the milk quantity which remains the same.

48/y = 3/4 , y being the total quantity after the addition of extra water.

y = 64, this means the water added was 4 lts.
Regards,
Harsha

Senior | Next Rank: 100 Posts
Posts: 84
Joined: Mon Apr 26, 2010 2:51 am
Thanked: 6 times
Followed by:1 members

by brijesh » Sat May 08, 2010 9:54 am
harshavardhanc wrote:
sanju09 wrote:A mixture of milk and water measures 60 liters. It contains 20 percent water. How many liters of water should be added to it so that water in the resulting mixture may be 25 percent?
(A) 4
(B) 5
(C) 6
(D) 8
(E) 10
two ways to solve this problem :

first, considering the water quantity.


the water in the solution is 12 lts, so (12+x)/(60+x) = 1/4

4x + 48 = 60 + x

x = 4 lts

second, if you consider the milk quantity which remains the same.

48/y = 3/4 , y being the total quantity after the addition of extra water.

y = 64, this means the water added was 4 lts.
I thought the first one:
water in mix=12 l
so (12+x)/(60+x)=1/4
x=4 only satisfies the condition.

thank u for highlighting the seconad way of looking.
brijesh

User avatar
Legendary Member
Posts: 1022
Joined: Mon Jul 20, 2009 11:49 pm
Location: Gandhinagar
Thanked: 41 times
Followed by:2 members

by shashank.ism » Sat May 08, 2010 7:25 pm
harshavardhanc wrote:
sanju09 wrote:A mixture of milk and water measures 60 liters. It contains 20 percent water. How many liters of water should be added to it so that water in the resulting mixture may be 25 percent?
(A) 4
(B) 5
(C) 6
(D) 8
(E) 10
two ways to solve this problem :

first, considering the water quantity.


the water in the solution is 12 lts, so (12+x)/(60+x) = 1/4

4x + 48 = 60 + x

x = 4 lts

second, if you consider the milk quantity which remains the same.

48/y = 3/4 , y being the total quantity after the addition of extra water.

y = 64, this means the water added was 4 lts.
The second approach is really a bit faster , will save a lot of time...
My Websites:
www.mba.webmaggu.com - India's social Network for MBA Aspirants

www.deal.webmaggu.com -India's online discount, coupon, free stuff informer.

www.dictionary.webmaggu.com - A compact free online dictionary with images.

Nothing is Impossible, even Impossible says I'm possible.