PREP Math & CR真心求解！！哪位大牛出手相助？

kexin2008

那道数学题在manhattan的论坛上的解释为：
Let’s break that down into separate steps:
“add 2 percent of one’s annual income to” the next thing
“average (arithmetic mean) of 100 units of country R’s currency and 1 percent of one’s annual income”
The average of 100 and 1 percent of R is (100 + 0.01R)/2. (The standard average formula is: average = sum / # of things.)
Then, what was that other part? Oh, yes, “add 2 percent of one’s annual income.” So that’s 0.02R and I should add it to my average above. That gives me:
0.02 R + (100+0.01 R)/2
Now I have to simplify this thing. I can split the right-hand term into two parts:
0.02 R + (100/2) + (0.01 R /2)
2R/100 + 50 + R /(100*2) = 2R /100 + 50 + R /200 = 4R /200 + 50 + R /200=
5R /200 + 50 = R /40 + 50