Question

There are 'mn' letters and n post boxes. The number of ways in which these letters can be posted is:

• A. $(mn{)}^n$
• B. $(mn{)}^m$
• C. $m{}^m{}^n$
• D. $n{}^m{}^n$

Answer 1

The correct option is D $n{}^m{}^n$

Every letter can be posted in any of the n post boxes

$\therefore$Total number of ways $=n\times n\times n\times ........\left(mntimes\right)=n^{mn}$