Question

Five couple are to line up for a photograph. In how many ways can they be arranged such that husbands must be next to their wives?

Answer 1

Explanation:

Considering a couple to be a single object i.e. 2 people as 1

In this way there are 5 object

No of ways in which 5 objects can be arranged is 5!

Husband and wife can be arranged in 2! ways

so total no of ways such that husband must be next to their wives

is
`=2!* 5!`

`=240\ ways`