Question

Number of ways in which 5 letters can be posted in 4 letter boxes is :

• A. $5^4$
• B. $20$
• C. $25$
• D. $4^5$

Answer 1

Answer: (D)

$4^5$

The first letter can be posted in any of the $4$ post boxes.

Therefore, it has $4$ choices.
Similarly, the second, the third, the fourth and the fifth letter can each be posted in any of the $4$ post boxes.
$\therefore$ The total number of ways the $5$ letters can be posted in $3$ boxes is $=4\times 4\times 4\times 4\times 4$ $=4^5$