求助一道数学PS题！难理解 谢谢！

adamilan

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

gina2012

add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of Country R's currency

we do not knwo the mean value !!!

adamilan

what do you mean?

add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of Country R's currency

we do not knwo the mean value !!!

-- by 会员 gina2012 (2012/5/23 18:49:13)

gina2012

B?

I don't quite understand the question

anitawin

R国的个人所得税=个人年收入的2%+个人收入1%与100单位R国货币的平均值，所以个人所得税=2%I+（1%I+100）/2 简化就好了。
100 units of currency（100单位的钱，类似于100元啊100刀这种）
注意:the average of A and B, 不要理解错了题意

soongrui

好像选C。
题目的意思是不是这样（直译）：化简之前，计算R国收入税的方式是个人年收入2%+（100单位R国货币与1%个人年收入）的平均数。那么求化简之前的式子就应该是：2%+（100+1%I）/2。
因此化简之后就应该是C：50+I/40

我的理解，请多指正~~明天考试，攒RP！

gina2012

好像选C。
题目的意思是不是这样（直译）：化简之前，计算R国收入税的方式是个人年收入2%+（100单位R国货币与1%个人年收入）的平均数。那么求化简之前的式子就应该是：因此化简之后就应该是C：50+I/40

我的理解，请多指正~~明天考试，攒RP！

-- by 会员 soongrui (2012/5/23 21:15:29)

if it is the case, should be 2% *I+（100+1%I）/2 ?

answer 50+ 3I/200?

I am confused

soongrui

对的，式子是你那么列的，我刚才打的时候漏了一个I。。。但是这样求出来也是C啊...2%+1%/2=1/40...不对吗？

sikypan

同意B。。。平均值应该是指100元与1%收入的平均值，看清楚to的位置就知道了。

soongrui

同意B。。。平均值应该是指100元与1%收入的平均值，看清楚to的位置就知道了。

-- by 会员 sikypan (2012/5/23 22:32:06)

那个值算出来是2.5%I...为什么会是B呢？