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?

Answer :

syed514
8C1*2C1*9C1
and the answer is 160

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