SOLUTION: A boy is now two-thirds as old as his sister, and two years ago he was five-eighths as old as she was then. Find their present ages.

Question 971816: A boy is now two-thirds as old as his sister, and two years ago he was five-eighths as old as she was then. Find their present ages.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A boy is now two-thirds as old as his sister, and two years ago he was five-eighths as old as she was then. Find their present ages.
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Equations:
b = (2/3)s
b-2 = (5/8)(s-2)
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Substitute and solve for "s"::
(2/3)s - 2 = (5/8)s - (10/8)
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Multiply thru by 24 to get:
16s - 48 = 15s - 30
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s = 78 yrs (sister's age now)
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Solve for "b":
b = (2/3)s
b = (2/3)78
b = 52 yrs (boy's age now)
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Cheers,
Stan H.
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