Question

A numerical pass-code is required to gain access to a website. The 4 digit pass-code uses the digits 0, 1, 2, 3, 4,and 5. Then numbers may also be repeated in the pass-code. How many pass-codes are possible?

Answer 1

The digits that can be used to form the password are 0, 1, 2, 3, 4, 5. They are 6 in number.

This means that each digit in the passcode can be any of the 6 digits given above.

Since there are 4 digits in the passcode, and each digit has 6 possible outcomes, then the number of possible passcodes will be:

$\Rightarrow6\times6\times6\times6=6^4=1296$

Therefore, the number of possible passcodes is 1296 passcodes.