SOLUTION: Jack is five years older than Sarah. In three years, Jack will be twice as old as Sarah. How old are they now?

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Question 758571: Jack is five years older than Sarah. In three years, Jack will be twice as old as Sarah. How old are they now?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +j+ = Jack's age now
Let +s+ = Sarah's age now
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given:
(1) +j+=+s+%2B+5+
(2) +j+%2B+3+=+2%2A%28+s+%2B+3+%29+
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By substitution:
(2) +s+%2B+5+%2B+3+=+2%2A%28+s+%2B+3+%29+
(2) +s+%2B+8+=+2s+%2B+6+%29+
(2) +s+=+8+-+6+
(2) +s+=+2+
and
(1) +j+=+s+%2B+5+
(1) +j+=+2+%2B+5+
(1) +j+=+7+
jack is 7 and Sarah is 2
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check:
(2) +j+%2B+3+=+2%2A%28+s+%2B+3+%29+
(2) +7+%2B+3+=+2%2A%28+2+%2B+3+%29+
(2) +10+=+2%2A5+
(2) +10+=+10+
OK