SOLUTION: Three years ago,Matt's age was half of Neth's age. If the sum of their ages today is 21, how old is Matt now?

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Question 854664: Three years ago,Matt's age was half of Neth's age. If the sum of their ages today is 21, how old is Matt now?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +m+ = Matt's age now
Let +n+ = Neth's age now
-----------------------
(1) +m+-+3+=+%281%2F2%29%2A%28+n+-+3+%29+
(2) +m+%2B+n+=+21+
--------------------------
(1) +2%2A%28+m+-+3+%29+=+n+-+3+
(1) +2m+-+6+=+n+-+3+
(1) +2m+-+n+=+3+
--------------------------
Add (1) and (2)
(2) +m+%2B+n+=+21+
(1) +2m+-+n+=+3+
+3m+=+24+
+m+=+8+
and
(2) +m+%2B+n+=+21+
(2) +8+%2B+n+=+21+
(2) +n+=+13+
Matt is 8
Neth is 13
------------
check:
(1) +m+-+3+=+%281%2F2%29%2A%28+n+-+3+%29+
(1) +8+-+3+=+%281%2F2%29%2A%28+13+-+3+%29+
(1) +5+=+%281%2F2%29%2A10+
(1) +10+=+10+
OK