Answer:
8
Step-by-step explanation:
Since there are 3 (an odd number) ages, the median is the middle one. So, we know two of the ages are 10 and 15. In order for the mean of the three ages to be 11, their total must be 33. The total of the two known ages is 25, so the remaining one must be ...
33 -25 = 8
The youngest child is 8.