I'm stumped with this as maths has never been my strong point......
"A boy has as many sisters as brothers but each sister has only half as many sisters as brothers."
How many boys and girls are there in the family?

Do you get the feeling its really homework for the parents? I'm trying to get my head around the language. Its like them double negative questions.

4 boys
3 girls

[Edited on 11/2/08 by james h]

b= number of boys
g= number of girls

if

A boy has as many sisters as brothers

then

b-1=s

ie the minus one because one boy is not counting himself when he says he has as many sis' as bro.

and

s-1=2b

because "each sister has only half as many sisters as brothers"

to summarise:

s-1=b/2
b-1=s

combine as quick as we can:

b-2=b/2
b=2b-4
b=4

stick that into either equation to get s, 3, as james said above.

I worked it out as 4 boys and 3 girls before scrolling down.

I started with a triangular daiagram.

Boy at the top, then at bottom rh corner put the brothers and bottom lh corner the sisters.

As you know the boy has the same number of brothers and sisters you can start with 1 x B and 1 x S at the bottom and increase until you get the answer.
Cover up one of the S's and you will see what i mean.


B

/
BBB SSS

This is why I hated maths

In one word - 'boring'

Could a subject be taught any duller? I envy people how find maths interesting as I'm sure in reality it a marvellous subject what with quantum physics and astronomy, but the people who teach it a school make it as much fun as going to the dentist.