The Gauss family has three boys aged 7 , a girl aged 14 , and a boy aged 15 . What is the mean (average) of the ages of the children?
(A) 9
(B) 7
(C) 11
(D) 14
(E) 10
The children in the Gauss family have ages $7,7,7,14,15$.

The mean of their ages is thus $\frac{7+7+7+14+15}{5}=\frac{50}{5}=10$.

ANSWER: (E)