请教一道PREP上的数学

ssxinxin

今天模考了一下，竟然有一道数学题看不懂的说~

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?  （答案是：50+I/40）

请教各位NN们这题什么意思啊，该怎么做？
万分感谢！！

jsmart

2%I+（100+1%I）/2=50+I/40

ssxinxin

看懂了看懂了，终于知道那个平均数实在哪里出现的~谢谢啦~

jsmart

看懂了看懂了，终于知道那个平均数实在哪里出现的~谢谢啦~

-- by 会员 ssxinxin (2012/7/28 19:11:46)

其实我也看了半天。。。