求教一道prep数学题 请指点

mingzhu99

Before being simplified, the instructions fo computing income tax in Country R were to add 2 percent of one`s annual income to the average of 100 units of Country R`s currency and 1 percent of one`s annual income.Which of the following represents the simplified formula for computing the income tax,in Country R`s currency,for a person in that country whose annual income is I?

A:50+I/200      B:50+3I/100       C:50+I/40         D:100+I/50         E:100+3I/100


这题的意思我完全不懂。。。。忘各位XDJM赐教~~~~

jiuwang

选B吗

mingzhu99

答案是C哦  我没看懂题目

ivychacha

2 percent of one`s annual income to the average of 100 units of Country R`s currency and 1 percent of one`s annual income
=>add(2% x I) to average(100 + 1%xI)
=>0.02I + 1/2(100 + 0.01I)
=>50 + 0.25I
=>50+I/40
=>C

jiuwang

啊！！！知道我错在哪儿了！！average修饰的是100 units of Country R`s currency and 1 percent of one`s annual income          所以就是100块和收入1%的平均数，是（100+1%I）/2    然后再用这个加上2%I，结果是50+I/40

mingzhu99

恩~~知道啦~谢谢~~