Answer to Question #289603 in Statistics and Probability for kjk

Question

A Store-It-All storage facility requires users to enter a four-digit code, using numbers 0-9, to get through the gate. You need to get a box of winter clothes from your storage container, but you forgot the code. 

1. How many possible codes are there if the digits cannot be repeated? 

There are Answer____ possible codes. 

Answer 1

For the first place of the code, there are 10 different digits possible.

For the second place of the code, there are 9 different digits possible.

In the third place of the code, there are 8 different digits possible and,

in the fourth place of the code, there are 7 different digits possible.

Therefore, there are $10\times 9\times 8\times 7=5040$ possible codes.