回复：first Q : 969 second Q:10626
guest1000
2010-09-08 12:23:06
( reads)
The answer to the second question should be C(19,4)+C(19,3)=C(20,4).
The answer to the second question should be C(19,4)+C(19,3)=C(20,4).
jinjing
2010-09-08 13:10:35I mean second Q; We can put 0 for 4 cases.So, the