A couple has three children. Assuming independence and that the probability of a boy is 1/2, determine the probability that at least one child is a girl.

Answer 1

There are 8 possible outcomes when a couple has three children:
- BBB
- BBG
- BGB
- GBB
- BGG
- GBG
- GGB
- GGG

Out of these 8 outcomes, 7 have at least one girl. Thus, the probability that at least one child is a girl is 7/8 or 0.875.