wxcfgh852014-11-15 20:40:36

Sandy has a husband and 2 children. She brings at least 1 member of her family to a diner for lunch every day. The diner offers 10 lunch specials. If no one orders the same thing, how many different orders can Sandy’s family make for lunch? Indicate all possible values.

答案选项分别是45,90,120,210,720, 5040

看看哪位高手能够算出来,而且给出计算的方法和过程?

wxcfgh852014-11-15 21:19:18
如果按题目的意思,是母亲可以带至多三个人,也就是共四个人去,每人选的菜各不相同,然后得到可能组合总数。
尚文2014-11-15 21:21:55
以前为这种东西拼死拼活,真是浪费青春。
水准2014-11-15 22:07:31
到底有几个正确答案?楼上的答案好像都不一样啊。
最爱口头禅2014-11-15 23:55:08
现在 GRE 有6个选项? 答案是 45 x 3 + 120 x 3 + 210 = 705, 所以选 None of the
勿来三2014-11-16 00:31:21
对的
勿来三2014-11-16 00:33:06
flyfish 是正确的