SOLUTION: Demtris is 14 years older than Sam. In 9 years he will be twice her age. How old are Demetris and sam?

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Question 273821: Demtris is 14 years older than Sam. In 9 years he will be twice her age. How old are Demetris and sam?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let d = Demetris's age now
Let s = Sam's age now
d+%2B+9 = Demetri's age in 9 years
s+%2B+9 = Sam's age in 9 years
given:
d+=+s+%2B+14
(1) d+-+s+=+14
and
d+%2B+9+=+2%2A%28s+%2B+9%29
d+%2B+9+=+2s+%2B+18
(2) d+-+2s+=+9
Subtract (2) from (1)
(1) d+-+s+=+14
(2) -d+%2B+2s+=+-9
s+=+5
and, from (1)
d+-+5+=+14
d+=+14+%2B+5
d+=+19
Demetri is 19 and Sam is 5
check:
d+%2B+9+=+2%2A%28s+%2B+9%29
19+%2B+9+=+2%2A%285+%2B+9%29
28+=+2%2A14
28+=+28
OK