SOLUTION: Judy is now three times as old as her niece, Jill. Seven years ago, she was five times as old as Jill was then. How old are Judy and Jill now?

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Question 736021: Judy is now three times as old as her niece, Jill. Seven years ago, she was five times as old as Jill was then. How old are Judy and Jill now?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +j+ = Judy's age now
Let +n+ = niece's age now
given:
(1) +j+=+3n+
(2) +j+-+7+=+5%2A%28+n+-+7+%29+
-----------------------
(2) +j+-+7+=+5n+-+35+
(2) +j+=+5n+-+28+
Substitute (1) into (2)
(2) +3n+=+5n+-+28+
(2) +2n+=+28+
(2) +n+=+14+
and
(1) +j+=+3%2A14+
(1) +j+=+42+
Judy is 42
Jill is 14
check:
(2) +j+-+7+=+5%2A%28+n+-+7+%29+
(2) +42+-+7+=+5%2A%28+14+-+7+%29+
(2) +35+=+5%2A7+
(2) +35+=+35+
OK