prep 中的一道数学题.在线等...

yalemba2007

 A manufacturer produced x percent more video cameras in 1994 than in 1993 and y percent more video cameras in 1995 than in 1994. If the manufacturer produced 1,000 video cameras in 1993, how many video cameras did the manyfacturer produce in 1995?

(1)xy=20

(2)x+y+(xy)/100 = 9.2

答案是b, 不解?

一个方程, 两个未知数, x, y值定不下来啊.

[此贴子已经被作者于2006-11-17 5:42:15编辑过]

jinyiming

1995=(1+y/100)*1994=(1+y/100)*(1+x/100)*1993

expand the equation