SOLUTION: Cake is twice as ild as moja. Ten years ago, cake was 3 times as old as moja. What are their present age?

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Question 1050543: Cake is twice as ild as moja. Ten years ago, cake was 3 times as old as moja. What are their present age?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = Cake's preent age
Let +b+ = Moja's present age
------------------------------
(1) +a+-+10+=+3%2A%28+b+-+10+%29+
(2) +a+=+2b+
------------------
(1) +a+-+10+=+3b+-+30+
(1) +-a+%2B+3b+=+30+-+10+
(1) +-a+%2B+3b+=+20+
---------------------
By substitution:
(1) +-2b+%2B+3b+=+20+
(1) +b+=+20+
and
(2) +a+=+2%2A20+
(2) +a+=+40+
------------------
Cake is 40
Moja is 20
------------
check:
(1) +a+-+10+=+3%2A%28+b+-+10+%29+
(1) +40+-+10+=+3%2A%28+20+-+10+%29+
(1) +30+=+3%2A10+
(1) +30+=+30+
OK