How many six-character code words can be formed if the first two characters are letters and the others are letters and/or digits?

Question

How many six-character code words can be formed if the first two characters are letters and the others are letters and/or digits?

IF REPETITION ISNT ALLOWED

Answer choices;

A)918,918,000

B)723,465,600

C)1,135,420,416

D)918,918,000

Answer 1

Since there is no repetition, we will remove 1 after each item is picked. The first 2 are letters, so that would be

26·25

After the first 2 letters, we add in ten more choices for the digits 0-9 to the remaining 24 letters. So in all:

26·25·34·33·32·31 = 723,465,600 (Answer B)