Question 390890: In 15 years, Maya will be twice as old as David is now. In 15 years, David will be as old as Maya will be 10 years from now. How old are Maya and David now?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! let m = M's age now
Let d = D's age now
:
write an equation for each statement:
:
"In 15 years, Maya will be twice as old as David is now.
m + 15 = 2d
or
m = 2d - 15; (we can use this form for substitution)
:
"In 15 years, David will be as old as Maya will be 10 years from now.
d + 15 = m + 10
d = m + 10 - 15
d = m - 5
Substitute (2d-15) for m (from the 1st statement)
d = (2d - 15) - 5
d = 2d - 20
d - 2d = -20
-d = -20
d = 20 yrs old now
find m
m = 2d - 15
m = 2(20) - 15
m = 25 yrs old now
:
:
Check solutions in the statement:
"In 15 years, David will be as old as Maya will be 10 years from now."
15 + 20 = 25 + 10
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