这是gmat模拟题（disclosed  edition test code 14）的section 7的一道数学题：

the organizers of a fair projected a 25 percent increase in attendance this year over that of last year, but attendance this year actually decreased by 20percent.What percent of the projected attendance was the actual attendance ?

a: 45%; b: 56%;  c:64% ; d: 75% ; e: 80%

都不知道是什么意思，拜托知道的同志帮忙解答一下！感激涕零！

thank you very much！

原来是这样的。我以为很难呢！