請問GWD13-Q18

[christinehsu]

A certain company that sells only cars and trucks reportes that revenues from car sales in 1997 were down 11 percent from 1996 and revenues from truck sales in 1997 were up 7 percent from 1996. If total reveunes from car sales and truck sales in 1997 were up 1 percent from 1996, what is the ratio of revenue from car sales in 1996 to revenue from truck sales in 1996?
A)1:2
B)4:5
C)1:1
D)3:2
E)5:3

answer:(A)

不好意思!我想請問這提
要怎麼代數或設未知數
謝謝!^^

[asicschu]

我來試著解釋一下:

設 revenues 如下:
car --> X ; truck--> Y

則依題目可得到下列等式:

0.89X+1.07Y=1.01(X+Y)

如此就可以得到 X : Y = 1 : 2 了!! ;)

[Quinton]

推啊∼
大大的解題真是精彩啊！！

[christinehsu]

真的很謝謝你!
非常清楚呢!^^