Question

Suppose a couple planned to have three children. Let X be the number of girls the couple has.

Answer 1

Answer:

a) {GGG, GGB, GBG, BGG, BBG, BGB, GBB, BBB}

b) {0,1,2,3}

c)

$P(X=2) = \dfrac{3}{8}$

d)

$P(\text{3 boys}) = \dfrac{1}{8}$

Step-by-step explanation:

We are given the following in the question:

Suppose a couple planned to have three children. Let X be the number of girls the couple has.

a) possible arrangements of girls and boys

Sample space:

{GGG, GGB, GBG, BGG, BBG, BGB, GBB, BBB}

b) sample space for X

X is the number of girls couple has. Thus, X can take the values 0, 1, 2 and 3 that is 0 girls, 1 girl, 2 girls and three girls from three children.

Sample space: {0,1,2,3}

c) probability that X=2

P(X=2)

That is we have to compute the probability that couple has exactly two girls.

$\text{Probability} = \displaystyle\frac{\text{Number of favourable outcomes}}{\text{Total number of outcomes}}$

Favorable outcome: {GGB, GBG, BGG}

$P(X=2) =\dfrac{3}{8}$

d) probability that the couple have three boys.

Favorable outcome: {BBB}

$P(BBB) = \dfrac{1}{8}$