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Ratio problem from OG13

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Ratio problem from OG13

by sohailmbaprep » Sun Jun 03, 2012 3:17 am
Q) 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 ?
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by mathbyvemuri » Sun Jun 03, 2012 4:33 am
S:A:W = 2:50:100
S:A is doubled => 4:50
S:W is halved => 1:100 which can also be written as 4:400
Final ratio of all three = 4:50:100
Ratio of alcohol to water is 50:100 = 1:2
a solution with 100cc of alcohol contains 200cc of water
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by sohailmbaprep » Sun Jun 03, 2012 4:43 am
mathbyvemuri wrote:S:A:W = 2:50:100
S:A is doubled => 4:50
S:W is halved => 1:100 which can also be written as 4:400
Final ratio of all three = 4:50:100
Ratio of alcohol to water is 50:100 = 1:2
a solution with 100cc of alcohol contains 200cc of water
Wrong answer...OG says answer is 800
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by GMATGuruNY » Sun Jun 03, 2012 4:53 am
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by mathbyvemuri » Sun Jun 03, 2012 11:26 am
@sohoilmbaprep, did you get where I went wrong?
the final ratio is 4:50:400 and not 4:50:100
Then S:A:W = 4:50:400
and hence, A:W = 50:400 = 1:8
so for a 100 cc alcohol, there is 800 cc water
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