请教prep1中一道数学题，各位NN帮帮忙

丁香花儿

Before being simplified,, the instructions for computing income tax in Country R were to add 2 percent of one's annual income to the average (arithmetic mean) 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

answer is: C

实在看不明白题目的意思，各位NN帮帮忙！谢谢。

丁香花儿

原来是这个意思，明白了，多谢。

summertao

在简化前，计算收入税的方法是把个人收入的2%加到一个平均数上，这个平均数

是100元这个国家的货币和个人收入的1%的平均数。

则计算公式为2%I+(100+1%

I)/2=I/50+50+I/200=4I/200+50+I/200=50+5I/200=50+I/40

则简化后的公式为50+I/40

karen_gao

根据题意， 算式如下：

2%I+(100+1%I)/2=50+I/40