这题答案是E~可以跟我讲一下思路&要怎么解吗? A committee of three people is to be chosen from four married couples. What is the number of different committees that can be chosen if two people who are married to each other cannot both serve on the committee? (A) 16 (B) 24 (C) 26 (D) 30 (E) 32
A certain city with a population of 132,000 is to be divided into 11 voting districts, and no district is to have a population that is more than 10 percent greater than the population of any other district. What is the minimum possible population that the least populated district could have? (A) 10,700 (B) 10,800 (C) 10,900 (D) 11,000 (E) 11,100作者: waigedet 时间: 2010-7-8 09:46
自顶一下~请大家帮帮忙~非常感谢作者: 沉睡的巨人 时间: 2010-7-8 10:13
关于那个committee的。。。先从4couple中选出3个couple，因为committee中的三个人不能couple，那么肯定是从三个不同的couple中选出来的，共有4种选法；然后从3个couple中选出3个人作为committee中的人，共有2×2×2=8种方法，那么4×8=32作者: avalon9527 时间: 2010-7-8 10:18
4对新人中选3人出来，3人不能含有一对新人。这种题目很容易算错的。一般都是先把4对新人每对看成一个整体。要求选3人，且不能有一对新人出现，那么可以想成先从4对人中选出3对人来，再从这3对人中各选一人(选的是男方还是女方？每对有C(2,1)种情况)。这样就不会出现一对的情况了。 算出来是C(4,3)*C(2,1)*C(2,1)*C(2,1)=32.
