Question

A family has three children. Assuming a boy is as likely as a girl to have been born, what are the following probabilities? Two are girls and one is a boy. Incorrect: Your answer is incorrect. At least 1 is a boy. Incorrect: Your answer is incorrect.

Answer 1

3/8 , 3/8

Explanation:

Assumption: A boy is as likely as a girl

hence P(B)= P(G)= 1/2= 0.5

family has 3 children

find the probability of

A) two girls and a boy.

it can happen in following way

BGG, GGB or GBG

P(BGG)= P(GGB)= P(GBG) =
`(1)/(2)*(1)/(2)*(1)/(2)`

= 1/8

therefore , probability of two girl and a boy=
`(1)/(8) +(1)/(8) +(1)/(8)` = 3/8

B) At least One boy

it can happen is in

BGG, BBG, BBB

P(BGG)= P(BBG)= P(BBB) =
`(1)/(2)*(1)/(2)*(1)/(2)`

= 1/8

therefore , probability of at least one boy=
`(1)/(8) +(1)/(8) +(1)/(8)` = 3/8