Complete the sentences based on the provided passages.

Formule : $P(1 \text{ enfant}) = P(\text{1er = garçon})$.

Substitution : $P(\text{1er = garçon}) = \frac{1}{2}$.

Simplification : $P = \frac{1}{2}$.

$$\boxed{\dfrac{1}{2}}$$

1. (b)

Formule : $P(2 \text{ enfants}) = P(\text{1er = fille}) \times P(\text{2e = garçon})$.

Substitution : $P = \frac{1}{2} \times \frac{1}{2} = \frac{