Question 185090
In 15 years, Maya will be twice as old as David is now. 
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In 15 years, David will be as old as Maya will be in 10 years from now. 
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How old are Maya and David now?
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Now DATA:
Let Maya be "m"; Let David be "d".
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15 years from now DATA:
Maya will be "m+15"; David will be "d+15"
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EQUATIONS:
(m+15) = 2d
(d+15) = m+10
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Rearrange the equations:
m - 2d = -15
m -  d =   5
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Subtract the 1st equation from the 2nd and solve for "d":
d = 20 (David's age now)
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Substitute in m - d = 5 to solve for "m":
m - 20 = 5
m = 25 (Maya's age now)
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Cheers,
Stan H.