zoeannz
contestada

A garage door opener has a 10 number key pad. The codes must be 5 digits long with no adjacent digits the same. How many codes are possible?

Respuesta :

Based on the same argument, the fourth and fifth digits also have 9 choices each.

Hence, the total number of possible codes are:

10 X 9 X 9 X 9 X 9

= 65610