Question

In how many ways can five children stand in a queue ?

Answer 1

The total number of ways
= Number of arrangements of 5 things, taken all at a time = $5_{P_5}=\frac{5!}{(5-5)!}=\frac{5\times 4\times 3\times 2\times 1}{0!}[\because 0!=1]$
=120 Hence, the totla number of ways in which children stand in a queue is 120.