Final answer:
The probability that neither child is a girl is 1/3.
Step-by-step explanation:
To find the probability that neither child is a girl, we can consider the possible combinations of children gender in a family with two children. There are four possible outcomes: BB, BG, GB, and GG, where B represents a boy and G represents a girl. However, we know that one of the children is a boy, so we can eliminate the GG outcome. This means we have three remaining outcomes, BB, BG, and GB, out of which only one outcome (BB) has neither child as a girl. Thus, the probability that neither child is a girl is 1 out of 3, or 1/3.