The number of ways in which four different letters can be put in the correspondingly four addressed envelopes so that no letters are put in the correct envelope, is

Options

A. 6
B. 7
C. 8
D. 9

Explanation

To solve the problem of finding the number of ways in which four different letters can be placed in four correspondingly addressed envelopes such that no letter is placed in the correct envelope, we can use the principle of inclusion-exclusion. Here’s a step-by-step solution:

### Step 1: Calculate the total arrangements of the letters
The total number of ways to arrange four different letters is given by the factorial of the number of letters. For four letters, this is:

\[ 4! = 24 \]
...