Question

How many ways can you choose a 8 digit passcode where all the digits are multiples of 2? (zero is NOT a multiple of 2)

Answer 1

`4^8=65,536`

Explanation:

We have 8 digits. We want all the digits to be multiples of 2, and so the digits 2, 4, 6, and 8 are allowed.

For each digit then, there are 4 choices.

If we had one digit, there'd be 4 ways to select.
If we had two digits, there'd be `4xx4=4^2=16` ways.
And so on.

We can write our ability to choose 8 digits as:

`4^8=65,536`