John wants to form 5 digit numbers from the set of integers from 0 to 9 inclusive. Assuming he can reuse numbers, and the 5 digit number must start with and 8 and end with a 0, how many different numbers may he form?

1 Answer
Apr 1, 2017

1000 possibilities

Explanation:

The first number must be an 8, so there is only 1 possibility for the first digit.
The second number can be anywhere between 0 to 9, so there are 10 possibilities for the second digit.
The third number can be anywhere between 0 to 9, so there are 10 possibilities for the second digit.
The fourth number can be anywhere between 0 to 9, so there are 10 possibilities for the second digit.
The fifth number must be a 0, so there is only 1 possibility for the last digit.

We multiply these possibilities to get 11010101=1000 possibilities.