SOLUTION: if bob is one third the age of his dad. in 12 years he will be half his age how old are they now?

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Question 441229: if bob is one third the age of his dad. in 12 years he will be half his age how old are they now?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Let b = Bob's present age
Let d = dad's present age
:
Write an equation for each statement:
:
"bob is one third the age of his dad."
b = 1%2F3d
Multiply by 3 to get rid of the fraction, results
3b = d
:
"in 12 years he will be half his age"
b + 12 = 1%2F2(d+12)
multiply by 2, to get rid of the fraction, results
2(b+12) = d + 12
2b + 24 = d + 12
2b = d + 12 - 24
2b = d - 12
Replace d with 3b, from the 1st statement:
2b = 3b - 12
12 = 3b - 2b
b = 12 yrs is bob's present age
:
I'll let you find dad's age, check the solution in the 2nd statement