Answer:
120 dolls total
Step-by-step explanation:
The number of dolls must be an integer, and that integer must be evenly divisible by 15 (as there are 15 groups).
If you'll write out multiples of 15, you'll get a sequence that looks like this:
{75, 90, 105, 120, 135, 150}
120 (dolls) is the only possible answer that suits here. 120/15 = 8. This is an integer. Each of the 15 groups of dolls contains 8 dolls.
