I am not sure what this question means 
$${\frac{\left({\mathtt{10}}{\mathtt{\,\small\textbf+\,}}{\mathtt{10}}{\mathtt{\,\small\textbf+\,}}{\mathtt{15}}{\mathtt{\,\small\textbf+\,}}{\mathtt{29}}{\mathtt{\,\small\textbf+\,}}{\mathtt{32}}\right)}{{\mathtt{5}}}} = {\frac{{\mathtt{96}}}{{\mathtt{5}}}} = {\mathtt{19.2}}$$
At the moment the average age is 19.2 years
Maybe it means that the average has to be between 13 and 25 
$$\\13<\frac{96+X}{6}<25\\\\
78<96+X<150\\\\
0
But really the person should be between 13 AND 25
I think that this is a dumb question 