Question

Customer account “numbers” for a certain company consists of 2 letters followed by 2 single-digit numbers. How many different account numbers are possible if repetition of letters and digits are allowed?

Answer 1

• 67600

Explanation:

Let the format be:

• LLDD- where L stands for letter and D- digit

For each L we have 26 (English alphabet) and for each D we have 10 options.

Number of possible accounts:

• 26*26*10*10 = 67600