SOLUTION: a is now 4 times as old as b .five year s ago a was 7 times as old as b was then. find the present age.

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Question 1011523: a is now 4 times as old as b
.five year s ago a was 7 times as old as b was then.
find the present age.
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
a is now 4 times as old as b:
a=4b.....eq.1
five years ago a was 7 times as old as b was then:
a-5=7%28b-5%29....eq.2
solve the system:
a=4b.....eq.1
a-5=7%28b-5%29....eq.2
------------------------------substitute a from eq.1 in eq.2
4b-5=7%28b-5%29....eq.2....solve for b
4b-5=7b-35
35-5=7b-4b
30=3b
highlight%28b=10%29-> the present age
then a=4b=> highlight%28a=40%29-> the present age