Question

if the births of boys and girls are equally likely, determine the probability that:

(A) In a family of two children there are:

(i) two girls (ii) no girl (iii) one girl and one boy

(B) In a family with three children there are:

(i) three boys (ii)two girls and one boy
(iii)more boys than girls

Answer 1

This question occupies millions of pages on the internet.

Answer 2

really? how hard is this?

Answer 3

unbelievably hard :) my answers are wrong lol

Answer 4

assuming equally likely and also assuming independence then there are four possibilities for first one
b, b
b, g
g, b
g, g

Answer 5

yep got that

Answer 6

What answers did you get when you tried it?

Answer 7

1/4,1/4,1/2

Answer 8

so
i) two girls: \[p=\frac{1}{4}\]

Answer 9

ii) no girls
\[p=\frac{1}{4}\]

Answer 10

I rember at uni, ju8st part 3 went on for about 150 posts...

Answer 11

Those are correct.

Answer 12

one girl and one boy
\[p=\frac{2}{4}=\frac{1}{2}\]

Answer 13

part B there are 8 possibilities

Answer 14

you can use a formula but 8 is so small you might as well list them

Answer 15

b b b
b b g
b g b
g b b
g g b
g b g
b g g
g g g

Answer 16

ok i got it lol

Answer 17

Actually, I think it was this

http://en.wikipedia.org/wiki/Boy_or_Girl_paradox

Answer 18

now it is a matter of counting. i am wondering why there is any problem here. like saying "toss three coins what is the probability that you get ..."

Answer 19

aah that is a different story. this is like

what is the probability the king has a sister. got it

Answer 20

i was using some unnecessary method

Answer 21

with 8 choices, might as well count

Answer 22

thanks heaps:)

Answer 23

i havent done probabilty for a while lol