SOLUTION: Help me answer this? Jack is twice as old as Jill. Into years Jack will be four times as old as Joel was nine years ago. How old are they now?

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Question 943759: Help me answer this?
Jack is twice as old as Jill. Into years Jack will be four times as old as Joel was nine years ago. How old are they now?
Found 2 solutions by josmiceli, MathLover1:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = Jack's age now
Let +b+ = Jill's age now
-------------------------
(1) +a+=+2b+
(2) +a+%2B+2+=+4%2A%28+b+-+9+%29+
-------------------------
(2) +a+%2B+2+=+4b+-+36+
By substitution:
(2) +2b+%2B+2+=+4b+-++36+
(2) +2b+=+38+
(2) +b+=+19+
and
(1) +a+=+2b+
(1) +a+=+2%2A19+
(1) +a+=+38+
Jack is 38
Jill is 19
------------
check:
(2) +a+%2B+2+=+4%2A%28+b+-+9+%29+
(2) +38+%2B+2+=+4%2A%28+19+-+9+%29+
(2) +40+=+4%2A10+
(2) +40+=+40+
-----------------
I think this is it. Work on your typing
It was terrible

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

Jack is twice as old as Jill.
Jack=2%2AJill....eq.1

In two years Jack will be four times as old as Jill was nine years ago.
Jack%2B2=4%2A%28Jill-9%29....eq.2
How old are they now?; solve the system:
Jack=2%2AJill....eq.1
Jack%2B2=4%2A%28Jill-9%29....eq.2....substitute Jack from eq.1

2%2AJill%2B2=4%2A%28Jill-9%29....eq.2
2%2AJill%2B2=4%2AJill-36
36%2B2=4%2AJill-2%2AJill
38=2%2AJill
38%2F2=Jill
highlight%28Jill=19%29
then
Jack=2%2AJill....eq.1
highlight%28Jack=38%29