SOLUTION: zelma is 18 years older than her son. She was three times as old as he was one year go. How old are they now

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Question 705606: zelma is 18 years older than her son. She was three times as old as he was one year go. How old are they now
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +z+ = Zelma's age now
Let +s+ = her Son's age now
given:
(1) +z+=+s+%2B+18+
(2) +z+-+1+=+3%2A%28+s+-+1+%29+
----------------------
Substitute (1) into (2)
(2) +s+%2B+18+-+1+=+3%2A%28+s+-+1+%29+
(2) +s+%2B+17+=+3s+-+3+
(2) +2s+=+20+
(2) +s+=+10+
and, since
(1) +z+=+s+%2B+18+
(1) +z+=+10+%2B+18+
(1) +z+=+28+
28 = Zelma's age now
10 = her Son's age now
--------------------
check:
(2) +z+-+1+=+3%2A%28+s+-+1+%29+
(2) +28+-+1+=+3%2A%28+10+-+1+%29+
(2) +27+=+3%2A9+
(2) +27+=+27+
OK