A round-table conference is to be held among 20 delegates belonging from 20 different countries. In how many ways can they be seated if two particular delegates are (i) always to sit together, (ii) never to sit together .

A family of 4 brothers and 3 sisters is to be arranged in a row for a photograph. In how many ways can they be seated if Q No two brothers are together.

In how many ways can 5 girls and 3 boys be seated in a row so that no two boys are together?

A family of 4 brothers and 3 sisters is to be arranged in a row for a photograph, in how many ways can they be seated if Q all the sisters sit together.

In how many ways can 3 ladies and 3 gentlemen be seated around a round table so that any two and only two of the ladies sit together?

Five boy and five girls sit alternately around a round table. In how many ways can this be done?

In how many ways 5 boys and 4 girls can be seated in a row so that no two girls are together.

There are 15 candidates for an examination . 7 candidates are appearing for mathematics examination while the remaining 8 are appearing for different subjects. In how many ways can they be seated in a row so that no two mathematics candidates are together ?

In how many ways can 5 boys and 3 girls sit in a row so that no two girls are together ?

There are 15 candidates for an examination. 7 candidates are appearing for mathematics examination while the remaning 8 are appearing for different subjects. In how many ways can they be seated in a row so that no two mathematics candidates are together?