SOLUTION: Five Years ago I was 5 times older than my son. In 8 Years I will be 3 times older than my son. How old am I today?

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Question 951004: Five Years ago I was 5 times older than my son. In 8 Years I will be 3 times older than my son. How old am I today?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +f+ = father's age now
Let +s+ = son's age now
--------------------------
(1) +f+-+5+=+5%2A%28+s+-+5+%29+
(2) +f+%2B+8+=+3%2A%28+s+%2B+8+%29+
--------------------------
(1) +f+-+5+=+5s+-+25+
(1) +5s+-+f+=+20+
and
(2) +f+%2B+8+=+3s+%2B+24+
(2) +-3s+%2B+f+=+16+
---------------------
Add the equations
(1) +5s+-+f+=+20+
(2) +-3s+%2B+f+=+16+
-------------------
+2s+=+36+
+s+=+18+
and
(2) +-3s+%2B+f+=+16+
(2) +-3%2A18+%2B+f+=+16+
(2) +-54+%2B+f+=+16+
(2) +f+=+70+
----------------
You are 70
Your son is 18
-------------
check:
(1) +f+-+5+=+5%2A%28+s+-+5+%29+
(1) +70+-+5+=+5%2A%28+18+-+5+%29+
(1) +65+=+5%2A13+
(1) +65+=+65+
and
(2) +f+%2B+8+=+3%2A%28+s+%2B+8+%29+
(2) +70+%2B+8+=+3%2A%28+18+%2B+8+%29+
(2) +78+=+3%2A26+
(2) +78+=+78+
OK