SOLUTION: John is now twice as old as Alexis, but six years ago he was five times as old as she was. How old is john now?

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Question 935619: John is now twice as old as Alexis, but six years ago he was five times as old as she was. How old is john now?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +j+ = John's age now
Let +a+ = Alexis's age now
---------------------------
(1) +j+=+2a+
(2) +j+-+6+=+5%2A%28+a-+6+%29+
-----------------------
Substitute (1) into (2)
(2) +2a+-+6+=+5%2A%28+a-6+%29+
(2) +2a+-+6+=+5a+-+30+
(2) +5a+-+2a+=+30+-+6+
(2) +3a+=+24+
(2) +a+=+8+
and, since
(1) +j+=+2a+
(1) +j+=+16+
John is 16 now
check:
(2) +j+-+6+=+5%2A%28+a+-+6+%29+
(2) +16+-+6+=+5%2A%28+8+-+6+%29+
(2) +10+=+5%2A2+
(2) +10+=+10+
OK