In how many ways 6 letters can be put in 6 addressed envelopes so that only 5 of them will go in the correct envelopes.
1
0
6!
277
In how many ways 6 letters can be put in 6 addressed envelopes so that only 3 of them will go in the correct envelopes?
6 letters are to be placed in 6 addressed envelopes. Each letter is assigned for an envelope. In how many ways these letters can be put in these envelopes such that exactly one letter goes in the correct envelope.