标题: GWD9-6 争议题 A 或C [打印本页] 作者: Kath1985 时间: 2012-10-21 15:28 标题: GWD9-6 争议题 A 或C Q6:
Sue’s monthly earnings consist of a monthly salary and a 4 percent commission on the portion of her monthly sales that is in excess of $2,000.If Sue’s monthly salary was the same in July as in August, how much greater were her sales in July than in August?
(1)Sue’s monthly earnings were $3,620 in July and $3,580 in August.
(2)Sue’s monthly salary was $3,500 in July and in August.
答案A 有人说C
我认为是A，思路如下，请问哪个步骤错了 ?
第一步:将条件一整理成联立方程式: (令X= 7月sales、 Y=8月sales)
( X -2000)4% + Base = 3620式子一
(Y - 2000)4% + Base = 3580式子二
第二步: 将式子一减式子二消掉共同的Base，得出
( X -2000)4% - (Y - 2000)4% = 40 式子三
第三步: 将式子三通分、得出X-Y值
0.04( X -2000) - 0.04( Y -2000) = 40
4( X -2000) - 4( Y -2000) = 4000 (通分)
( X -2000) - ( Y -2000) = 1000 à得出X-Y=1000
作者: Vin0960 时间: 2017-11-29 01:23
Only if the sales greater than $2000, you could use this way. (C) is correct.