Question

Find the number of ways in which 5 letters can be posted in 3 post boxes if any number of letters can be posted in a post box.

Answer 1

There are 5 letters and 3 post boxes and any number of letters can be posted in all three post boxes.
∴ Each letter can be posted in 3 ways.
∴ Total number of ways in which 5 letters can be posted = 3 × 3 × 3 × 3 × 3 = 243