Rek
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| posted on 11/2/08 at 08:42 PM |
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Can someone help with my sons year 7 maths homework please!!
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?
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mistergrumpy
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| posted on 11/2/08 at 09:00 PM |
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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.
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james h
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| posted on 11/2/08 at 09:04 PM |
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4 boys
3 girls
[Edited on 11/2/08 by james h]
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JoelP
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| posted on 11/2/08 at 09:16 PM |
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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. 
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DarrenW
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| posted on 12/2/08 at 11:47 AM |
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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
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Mr Whippy
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| posted on 12/2/08 at 01:45 PM |
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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.
Fame is when your old car is plastered all over the internet
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