Question

The access code for a vault consists of four digits. The first digitmust be even and the last digit cannot be a zero. How many possiblecodes are there?

Answer 1

The Solution.

The number of codes for the first digit = 5

The number of code of the second digit = 10

The number of code of the third digit = 10

The number of code of the four-digit = 9

So,

The number of possible codes is

`5*10*10*9=4500\text{ codes}`