Question

In how many ways can 5 letters be mailed if there are 2 mailboxes available?

Answer 1

$first \: mailbox \: and \: second \: mailbox \\ 0 \: and \: 5\\ 1 \: and \: 4 \\ 2 \: and \: 3 \\ 3 \: and \: 2 \\ 4 \: and \: 1 \\ 0 \: and \: 5$

may it will help you