OG11(黄皮）-217 概率问题

liangyun_105 · 发表于 2009-12-28 19:28:20

217. A certain junior class has 1,000 students and a certain senior class has 800 students. Among these students, there are 60 sibling pairs, each consisting of 1 junior an 1 senior. If 1 student is to be selected at random from each class, what is the probability that the 2 students selected will be a sibling pair?

(A) 3/40,000

(B) 1/3,600

(C) 9/2,000

(D) 1/60

(E) 1/15

Choose A

Question: 这个题目的思路应该是怎样的？

谢谢各位达人，多多指点～

sdfghjklzxcv · 发表于 2009-12-28 21:53:10

60/(1000*800)

OG11(黄皮）-217 概率问题

所属分类: GMAT考试

正在浏览此版块的会员 ()