请帮我看看这个“巨难”的数学题吧

zhipei

不好意思，标题党了。哎在我看来真是难挨，看都看不懂！这是我在今天做prep莫考的时候碰见的：

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

zhipei

这个要念对题目
Country R 的income tax 是这么算的： (年收入的2％) +  (100 和 年收入的1％ 的算术平均直)  
原文说 add (年收入的2％) to (100 和 年收入的1％ 的算术平均直)
年收入是I,  那么税是   2％* I +  (100+1%*I)/2 = 50+I/40

-- by 会员 chinamerica (2010/10/28 11:52:43)

多谢牛牛指教！看来还是理解太差。谢谢，想了一下午了都。。。。

2010

JUST   "2 percent of one's annual income " +  "the average (arithmetic mean)"

the average :  ( [100 units of Country R's currency ]+[ 1 percent of one's annual income])/2

1% of income
which shall be I/100

now average will be

(100 + I/100) / 2

50 + I/200

Now the result will be

I/50 + 50 + I/200
=50 + 5I/200
=50 + I/40

chinamerica

这个要念对题目
Country R 的income tax 是这么算的： (年收入的2％) +  (100 和 年收入的1％ 的算术平均直)  
原文说 add (年收入的2％) to (100 和 年收入的1％ 的算术平均直)
年收入是I,  那么税是   2％* I +  (100+1%*I)/2 = 50+I/40