Question

In how many ways can six persons be seated in a row ?

Answer 1

First person can be seated in a row in 6 ways. Second person can be seated in a row in 5 ways. Third person can be seated in a row in 4 ways. Fourth person can be seated in a row in 3 ways. Fifth person can be seated in a row in 2 ways. Hence, total number of ways in which six persons can be seated in a row = $6\times 5\times 4\times 3\times 2\times 1=720.$