In a family with two children, what are the probabilities of the following outcomes, assuming that the birth of boys and girls is equally likely?

Question

a. Both are boys.
b. The first is a girl and the second a boy.
c. Neither is a girl.
d. At least one is a girl.

I was wondering about the formula....

is a. P(probability) = 1/2(boy) + 1/2(boy)
P = 1/2 + 1/2
so P = 2/2
to me this doesn't seem right

Answer 1

A) PR(B,B)=Pr(b)*Pr(b)=1/2*1/2
B) Pr(g)Pr(b)=1/2*1/2
C) you can get at least one girl these ways:
gb
bg
gg

Pr(at least one g)= 1/2*1/2*3

Answer 2

Thank you for answering my question.
Why do you multiply the probability of both boys, girl and boy, etc?