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

1 Answer
Apr 10, 2016

Answer:

32

Explanation:

We can mail N letters in one box, and the remaining #5- N# in the other, for N = 0, 1, 2, 3, 4, 5.
We can select N out of 5 in #5C_N# ways.
So, the total number of all possible ways is #sum5C_N#, N = 0, 1, 2, 3, 4, 5.
This sum is 1 + 5 + 10 + 10 + 5 + 1 = 32.