SOLUTION: Sydney's present age is one-half of Marcus's present age. In 12 years, Sydney's age will be five-eighths of Marcus's age. Find their present ages.

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Question 269378: Sydney's present age is one-half of Marcus's present age. In 12 years, Sydney's age will be five-eighths of Marcus's age. Find their present ages.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Sydney's present age is one-half of Marcus's present age.
In 12 years, Sydney's age will be five-eighths of Marcus's age.
Find their present ages.
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Equations:
S = (1/2)M
(S+12) = (5/8)(M+12)
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Substitute for "M" and solve for "S":
S+12 = (5/8)(2S+12)
8S + 96 = 10S + 60
2S = 36
S = 18 (Sydney's age now)
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Since M = 2S, M = 36 (Marcus's age now)
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Cheers,
Stan H.