prep一道数学，大家帮我解一下

staren21cn

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
答案是C题目怎么理解啊

staren21cn

感谢解惑~！

bloomers

楼上正解

xiangzhengj

the average of 说的是后面两个的平均 就是（100+1%I）/2,再加上2%I就是C了