Question

a recently married couple are planning to have four children. They are equally likely to have a boy as well as a girl. What is the probability that they will have three boys and one girl?

Answer 1

0.25

Explanation:

Given that a recently married couple are planning to have four children. They are equally likely to have a boy as well as a girl.

Let X be the no of boys the couples have. X has two outcomes with p = 0.5

X is binomial with n = no of trials = 4 and p =0.5

the probability that they will have three boys and one girl

=
`P(X=3)\\=4C3(0.5)^3(0.5)\\= 0.25`

Reqd prob = 0.25