[求助]请教PREP中两道DS题

hmznb

1.if the drama club and music club are combined,what percent of the combined membership will be male?

(1)of the 16 members of the drama club,15 are male.

(2)of the 20 members of the music club,10 are male.

我选了C  答案是E  是不是我题目理解错了?

 

2.a manufacturer  produced X percent more video cameras in 1994 than in 1993 and Y percent more video cameras as in 1995 than in 1994.if it produced 1000 v-c in 1993,how many v-c did the manufacturer produce in 1995?

(1) xy=20

(2)x+y+xy/100 =9.2

我选了C  答案是B  我怎么也算不出来 不知道是哪里不对

村民乙

第一道题，你不知道有几个人本身就同时是两个club的成员；

第二道题   应该是1000*（1+X）*（1+Y）=1000*（1+X+Y+XY） 所以（2）单独可以

hmznb

谢谢 第1明白了

可是第2还是不太明白怎么算 1+x+y+xy  怎么通过条件2得出呢  那个xy/100不知道应该怎么用进去