A person write 4 letters and addresses 4 envelopes. If the letters are placed in the envelopes at random, then the probability that all letters are not placed in the right envelopes, is a. 1/4           b. 11/24            c. 15/24          d. 23/24

Explanation

To solve the problem of finding the probability that all letters are not placed in the right envelopes, we can follow these steps:

### Step 1: Calculate the total arrangements of letters in envelopes
The total number of ways to arrange 4 letters in 4 envelopes is given by the factorial of the number of letters.

\[ \text{Total arrangements} = 4! = 24 \]
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