Before 1995, three-digit area codes for the united states had the following restrictions:
(a) neither 0 nor 1 could be used as the first digit.
(b) 0 or 1 had to be used for the second digit.
(c) there were no restrictions on the third digit.

How many different area codes were possible?

Question

Before 1995, three-digit area codes for the united states had the following restrictions:
(a) neither 0 nor 1 could be used as the first digit.
(b) 0 or 1 had to be used for the second digit.
(c) there were no restrictions on the third digit.

How many different area codes were possible?

anonymous · Answer

160

anonymous · Answer

counting principle for this one
8 choices for the first number
2 for the second 
10 for the third
multiply these together get @Dallasb22  answer

anonymous · Answer

Sorry for posting the answer without explanation :/