12. The product of the ages of a father and his son is 2015 . What is the difference between their ages?
A 29
В 31
C 34
D 36
E None of these
12. C The prime factor decomposition of 2015 is $5 \times 13 \times 31$, so the only possible pairs of ages are $1 \times 2015,5 \times 403,13 \times 155,31 \times 65$. The only realistic pair of ages is 65 and 31 , with a difference of 34 .