一元方程文字題 快！！！

Let $a and $s be the amount of money Alan and Scott owned respectively

0.9(a+s)=a..............(1)
0.85(a+s)=a-16.......(2)

From (1),
0.9(a+s)=a
0.9a+0.9s=a
0.9s=0.1a
a=9s........................(3)

Sub. (3) into (2),
0.85(a+s)=a-16
0.85(9s+s)=9s-16
8.5s=9s-16
16=0.5s
s=32

Sub. s=32 into (3)
a=9s
a=9(32)
a=288

Therefore, Alan and Scott have $288 and $32

The sum of the money = $(288+32)=$320

2013-07-30 20:56:52 補充：
Some steps can be omitted. I just want you to understand the calculation easily.

2013-07-30 20:57:29 補充：
Correction:

Therefore, Alan and Scott have $288 and $32 respectively.

2013-07-31 22:37:34 補充：
Alan擁有的錢為$a
Scott擁有的錢為$s
2人共有$(a+s)

Alan佔整體的90%
所以a=(a+s)x90%
a=0.9(a+s)...(1)

當Alan給Scott$16的時候
Alan的錢就會變成$(a-16)
而他有的錢會變成整體的85%
整體的錢是不變的
所以a-16=(a+s)x85%
a-16=0.85(a+s)...(2)

明白了嗎??