SOLUTION: word problems solver: Jen is 7 years younger than Melissa. in 4 years Jen will be 1 year older than half of Melissa's age at that time. How old is Jen and Melissa?

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Question 1143189: word problems solver: Jen is 7 years younger than Melissa. in 4 years Jen will be 1 year older than half of Melissa's age at that time. How old is Jen and Melissa?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = Jen's age now
Let +b+ = Mellisa's age now
-----------------------------------
(1) +a+=+b+-+7+
(2) +a+%2B+4+=+%281%2F2%29%2A%28+b+%2B+4+%29+%2B+1+
-----------------------------------------
You can substitute (1) into (2)
(2) +b+-+7+%2B+4+=+%281%2F2%29%2A%28+b+%2B+4+%29+%2B+1+
(2) +b+-+3+=+%281%2F2%29%2A%28+b+%2B+4+%29+%2B+1+
(2) +b+-+4+=+%281%2F2%29%2A%28+b+%2B+4+%29+
Multiply both sides by 2
(2) +2%2A%28+b+-+4+%29+=+b+%2B+4+
(2) +2b+-+8+=+b+%2B+4+
(2) +b+=+12+
and
(1) +a+=+b+-+7+
(1) +a+=+12+-+7+
(1) +a+=+5+
----------------------------
Jen is 5
Mellisa is 12
--------------------
check:
(2) +a+%2B+4+=+%281%2F2%29%2A%28+b+%2B+4+%29+%2B+1+
(2) +5+%2B+4+=+%281%2F2%29%2A%28+12+%2B+4+%29+%2B+1+
(2) +9+=+%281%2F2%29%2A16+%2B+1+
(2) +9+=+8+%2B+1+
(2) +9+=+9+
OK
You can check (1)