# In how many ways can 7 letters be posted in 4 letter boxes?

Question:

In how many ways can 7 letters be posted in 4 letter boxes?

Solution:

Each letter can be posted in any one of the 4 letter boxes.

Number of ways of posting one letter = 4

$\therefore$ Required number of ways of posting the 7 letters $=4 \times 4 \times 4 \times 4 \times 4 \times 4 \times 4=4^{7}$