C*****D
发帖数: 1299 | 1 how about another math problem?
A,B,C,D,E, F have internet accounts. Some, but not all, of them are internet
friends with each other, and none of them has an internet friend outside
this group. Each o them has the same number of internet friends. In how many
different ways can this happen?
A. 60 B, 170 C. 290 D, 320 E, 660 |
|
