There are four chairs with two chairs in each row. In how many ways can four persons be seated on the chairs, so that no chair remains unoccupied

In how many ways can 20 persons be seated round a table if there are 9 chairs?

In how many ways can 20 persons be seated round a table if there are 9 chairs.

In how many ways 6 girls can be seated in two chairs ?

In how many ways 12 boys can be seated on 10 chairs in a row so that two particular boys always take seat?

In how many ways can 5 people occupy 8 vacant chairs?

In a class room there are 10 rows and in each row there are 2 chairs. In how many ways 10 boys and 10 girls can be arranged in these 20 chairs so that in each row one girl and one boy must be seated

Find the number of ways in which four persons can sit on six chairs.