Question

The access code for a cars security system consists of four digits. The first digit cannot be zero and the last digit must be odd. How many different codes are available​

Answer 1

4500

Explanation:

The first digit cannot be 0; therefore, we have 9 choices (1-9, inclusive).

The second and third digits can both be whatever they like, so we have 10 choices for both (0-9, inclusive).

The fourth digit has to be odd, so we have 5 choices (1, 3, 5, 7, 9).

So!

9 * 10 * 10 * 5 = 4500 :))