Ratio Problem OG 192

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Ratio Problem OG 192

by HPengineer » Mon Aug 09, 2010 8:03 pm
The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol how many cubic centimeters of ware will it contain?

A.) 50
B.) 200
C.) 400
D.) 624
E.)800

Anyone have an cool tricks for this problem? its really bugging me...
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by 4GMAT_Mumbai » Mon Aug 09, 2010 8:47 pm
Hi,

S:A:W = 1:25:50

Ratio of soap to alcohol is doubled. Current ratio = 1:25.

Double it and you get 2:25.

So, add 1 part soap to this solution and the overall ratio becomes 2:25:50.

Ratio of soap to water is halved. Original ratio = 1:50.

Halve it and you get 1:100; which is equivalent to 2:200.

Add 150 parts of water to the previous solution and the new ratio becomes 2:25:200

S:A:W = 2:25:200 which is equivalent to 8:100:800.

Why are we doing this? Because the question says that there are 100 cc of alcohol.

Hence, it has 800 cc of water in it.

Hope this helps. Thanks.
Naveenan Ramachandran
4GMAT, Dadar(W) & Ghatkopar(W), Mumbai

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by HPengineer » Wed Aug 11, 2010 8:42 am
yup now i got this problem... hopefully no problem like this will never give me trouble again Thanks for the help

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by selango » Wed Aug 11, 2010 8:47 am
S:A:W=2:50:100

Altered Solution:

S:A=4:50 or A:S=25:2

S:W=1:100 or S:W=2:200

A:S:W=25:2:200 or S:A:W=2:25:200

A:W=25:100 or A:W=100:800

Pick E
--Anand--