Question

A couple is planning to have three children. Each child is equally likely to be a boy or a girl. If this couple's plan is successful, what is the probability that they will have exactly two girls?

Answer 1

The probability of having exactly two girls is 3/8 or 0.375

Explanation:

Since the likelihood is equal, the probability of having a boy = probability of having a girl = 1/2

In written form;

P(g) = P(b) = 1/2

We use the Bernoulli approximation to know the probability of having two girls.

Mathematically, that would be;

3C2 P(g)^2 P(b)^1

Inserting the values , we have;

3 * (1/2)^2 * (1/2)

= 3 * (1/2)^3 = 3/8 = 0.375