[問題]GMAT PREP1 - PS

[a16327]

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 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)

Ans: C
看不懂到底如何得出此答案

[waleaaa]

呵...這題我也看了很久...
題目是說─
add 2 percent of one's annual income to the average of 100 units of Country R's currency and 1 percent of one's annual income
所以公式是─
　 (2% * I) + [(100 + 1% * I) / 2]
＝ (2% * I) + (50 + 0.5% * I)
＝ 50 + (2% + 0.5%) * I
＝ 50 + 2.5% * I
＝ 50 + (2.5/100) * I
＝ 50 + (I / 40)　　所以選C