A man is 42 years old and his son is 12 years old. In how many years will the age of the son be half the age of the man at that time? Explain!

After x years have passed, his father will be twice the age of the boy.
The age at this time of the father will be 42+x and the age of the son will be 12+x.
At that time, we know that the father is twice as old, so 42+x = 2(12+x)
Multiplying this out gives 42+x = 24+2x.
Adding -24-x to both sides gives  18 = x.

To check, let's see what happens 18 years from now.  The dad will be 42 + 18 = 60 and
the son will be 12 + 18 = 30.  Since 60 is twice 30, that's the right answer.


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Scott A Wilson


Any algebraic question you've got. That includes question that are linear, quadratic, exponential, etc.


I have solved story problems, linear equations, parabolic equations. I have also solved some 3rd order equations and equations with multiple variables.

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MS at math OSU in mathematics at OSU, 1986. BS at OSU in mathematical sciences (math, statistics, computer science), 1984.

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