A man throws a basket ball in a hoop to win a Kewpie doll. His probability of winning on each throw is 0.1. The man has three children, and he must win a Kewpie doll for each one.
What is the probability that 10 throws will be required to win the three dolls?
I thought the answer was (.9)^7(.1)^3 although this is not the answer in the book. It says the answer is 0.01722. What am I doing wrong?