SOLUTION: if A was foue times as old as B 8 years ago, and if A will be twice as old as B 8 years hence how old is B now?

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Question 1038781: if A was foue times as old as B 8 years ago, and if A will be twice as old as B 8 years hence how old is B now?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = A's age now
Let +b+ = B's age now
-------------------------
(1) +a+-+8+=+4%2A%28+b+-+8+%29+
(2) +a+%2B+8+=+2%2A%28+b+%2B+8+%29+
-----------------------
(1) +a-+8+=+4b+-+32+
(1) +-+a+%2B+4b+=+24+
and
(2) +a+%2B+8+=+2b+%2B+16+
(2) +a+-+2b+=+8+
-----------------------
Add the equations
(1) +-+a+%2B+4b+=+24+
(2) +a+-+2b+=+8+
--------------------
+2b+=+32+
+b+=+16+
and
(2) +a+-+2b+=+8+
(2) +a+-+2%2A16+=+8+
(2) +a+=+8+%2B+32+
(2) +a+=+40+
-------------------
A is 40 now
B is 16 now
-------------
check:
8 yrs ago, A was 32
8 yrs ago, B was 8
A was 4 times B
OK
-------------------
In 8 yrs, A is 48
In 8 yrs, B is 24
A will be twice B
OK