Question

A bank requires that its customers create a PIN to access their account. The pin must be 2 letters followed by 2 numbers. How many unique PINS are there if letters can be repeated but digits cannot be repeated?

Answer 1

Answer:

There are 60840 unique PINS if letters can be repeated but digits cannot be repeated

Step-by-step explanation:

In total, there are 26 letters and 10 digits.

The PIN has the following format:

L - L - N - N

The letters can be repeated, so for both letters, there are 26 options.

The digits cannot be repeated. So for the first digits there are 10 options. For the second there are 9, since the first digit used cannot be repeated.

In total:

26 - 26 - 10 - 9

26*26*10*9 = 60840

There are 60840 unique PINS if letters can be repeated but digits cannot be repeated