AAPL wrote:Today Jim is twice as old as Fred, and Sam is 2 years younger than Fred. Four years ago Jim was 4 times as old as Sam. How old is Jim now?
A. 8
B. 12
C. 16
D. 20
E. 24
We can PLUG IN THE ANSWERS, which represent Jim's current age.
When the correct answer is plugged in, Jim's age four years ago will be 4 times Sam's age four years ago.
B: J=12
Since Jim is twice as old as Fred, F=6.
Since Sam is 2 years younger than Fred, S=4.
Four years ago, J = 12-4 = 8 and S = 4-4 = 0.
Since Sam's age four years ago must be positive, all of the ages must increase in value.
Thus, a bigger answer choice is needed.
Eliminate A and B.
D: J=20
Since Jim is twice as old as Fred, F=10.
Since Sam is 2 years younger than Fred, S=8.
Four years ago, J = 20-4 = 16 and S = 8-4 = 4.
Success!
Jim's age four years ago is 4 times Sam's age four years ago.
The correct answer is
D.
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