一道很困惑的GWD5题

rabbit861013

题目其实我觉得很简单，可是我的答案就是和答案不一样，是答案错了吗？请指教。。。

Enrollment in City College in 1980 was 83 1/3 percent of enrollment in 1990. What was the percent increase in the college's enrollment from 1980 to 1990?

A.10%

B.16 2/3%

C.20%

D.25%

E.183 1/3%

rabbit861013

请问没人回答吗？是否觉得太简单了。但也请帮帮忙吧。大牛们。答案是C可我觉得答案是B

joe_ufoman

I will take it.

X:Enrollment in City College in 1980

Y:Enrollment in City College in 1990

Then X=Y times 83 1/3%

The percent increase means (Y-X)/X, the answer is 20%

brightxray

设1990 ENROLLMENT 为 X, 则1980 为 83 1/3%X

(X-83 1/3%X)/83 1/3%X    推出  16 2/3 比 83 1/3, 约分得 1/5, 所以是20%.