A clerk has 4 different letters that need to go in 4 different envelopes. What is the probability that all 4 letters are placed in the correct envelopes?
The probability that all
Let us first question how many ways are there in which we can place
The answer is
But there is only one way of pacing letters in correct envelopes, of course assuming that addressees areall different.There are
Hence, the probability that all