To find the total number of ways in which the middle letter is ' M ', we need to choose 2 letters from the set {A,B,C,...,L} and 2 letters from the set {N,O,P,...,Z}. The chosen letters must be arranged in alphabetical order with ' M ' in the middle. Step by Step Solution: Step 1 There are 12 letters before ' M ' ( A to L ) and 13 letters after ' M ' ( N to Z ). Step 2 We need to choose 2 letters from the 12 letters before ' M '. This can be done in (
12
2
) ways. Step 3 We need to choose 2 letters from the 13 letters after ' M '. This can be done in (
13
2
) ways. Step 4 The total number of ways is the product of these combinations: (