A couple has 3 children (considering binary gender). (a) What is the probability that all are girls if the two elder ones are girls? (b) What is the probability that the third one is a girl if you don’t have any knowledge about the first two children? I got the answer 1/2 for the two parts. Is that correct? For the first part, I divided the probability of the first two kids being girls and third also being a girl (1 * 1 * 1) with the probability of two elder kids being girls and third either being a girl or boy (1 * 1 * 2)
For the second part i simply divided probability of third child being a girl (2 * 2 * 1) by total number of combinations for 3 kids (2 * 2 * 2)