數學題,幫下手!

Let $y be the money she put in the bank,

y x 16% x 2 + y = 660
0.32 y + y =660
1.32 y = 660
y = 500

Therefore, she put $500 in the bank.

2007-08-28 23:20:53 補充：
To the people below...It is not mentioned that we need to calculate the compounded interest. Therefore, we should calculate it with simple interest.Thanks.

Let's y be the money that she put in the bank.
[(1+16%)y]1+16%=660
(1.16y)1.16=660
y=660/1.16*1.16
y=660/1.3456
y=490.48751(循環小數)

驗算:490.48751*1.16(第一年)*1.16(第二年)
=568.9655116...*1.16
=659.9999934

calculate by your self , see whether it's right or wrong.(by calculator)>(oo)

2007-08-28 20:58:04 補充：
(oo)

The money that she put in the bank
= $660 / ( 1 + 2 x 16%) (calculation based on simple interest)
= $500

Let the money is Y:
Y x (1+16%)^2 = 660
Y x 1.16^2 = 660
Y x 1.3456 = 660
Y = 660 / 1.3456
Y = 490.49