數學題１條！唔同之前果條架！

Let x be the no. of $100 banknotes.
100x+8x*20+(3*8)x*10=1500
100x+160x+24x*10=1500
100x+160x+240x=1500
500x=1500
x=1500/500
x=3

希望幫到你~=]

Let p be the no. of $100 banknotes,
100p+8px20+(3x8)px10=1500
100p+160p+24px10=1500
100p+160p+240p=1500
500p=1500
p=1500/500
p=3
so she has 3$100 banknotes,

let the number of $100 banknotes she had was x.
x乘100+8x乘20+8x乘3乘10=1500
100x+160x+240x=1500
500x=1500
x=3
the number of $100 banknotes she had was 3

2006-10-17 21:49:02 補充：
我計左好耐,希望幫到你手啦

Let y be no of $100 banknotes

If Alice had $1500

1500 = y x $100 + (8)y x $20 + (8 x 3)y x $10
1500 = 100y + 160y + 240y
1500 = 500y
y = 1500/500
y = 3

that means
$100 x 3(no. of banknote) = $300
$20 x (3 x 8) = $480
$10 x (3 x 8 x 3) = $720

$300+$480+$720 = $1500

actually it's quite easy....
I'm not sure you have ask the right question or not ....
Let a be the number of $100 banknotes
so 8a be the number of $20 banknotes
and 8a x 3 be the number of $10 banknotes

all add together was $1500

100a + 20x(8a) + 10x(8ax3) = 1500
100a + 160a + 240a = 1500
500a = 1500
a = 3
so she had 3 $100 banknotes.

is it ok??