Carcass wrote:
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 water will it contain?
A. 50
B. 200
C. 400
D. 625
E. 800
S : A : W = 2 : 50 : 100
The solution will be altered so that the ratio of soap to alcohol is doubledThe ORIGINAL ratio is S : A = 2 : 50.
NEW ratio is S : A = 4 : 50
the ratio of soap to water is halvedThe ORIGINAL ratio is S : W = 2 : 100
NEW ratio is S : W = 1 : 100
If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain? We need to COMBINE our two ratios.
Take S : W = 1 : 100 and create the EQUIVALENT ratio S : W = 4 : 400
We can now combine both ratios to get: S : A : W = 4 : 50 : 400
We want water = 100
So, take S : A : W = 4 : 50 : 400 and rewrite as S : A : W = 8 : 100 : 800
Answer: E
Cheers,
Brent
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Brent Hanneson - founder of Greenlight Test Prep