Question

Suppose a family has four children. What is the probability that at least two are female?

Answer 1

P(all 4 are male) = 1/2^4 = 1/16  ( assuming  probability of 1 male = 1/2)

P( 3 are male) =   1/2^4*4  = 1/4

The rest will have at least 2 females

So probability of at least 2 females) = 1 - 1/16 - 1/4 =  1 - 5/16 = 11/16 answer