1003024602

SubArea: 
Combinatorics
Level: 
A
Project ID: 
1003024602
Accepted: 
1
Clonable: 
0
Easy: 
0
Suppose six pupils are sitting on six chairs in a row. Among them there are twins. In how many ways can the pupils be seated in the row so that the twins do not sit next to each other?
6!−2⋅5!=480
6!2=360
2⋅5!=240
6!−5!=600