How many end office codes were there pre-1984, when each end office was named by its three-digit area code and the first three digits of the local number? area codes started with a digit in the range 2–9, had a 0 or 1 as the second digit, and ended with any digit. the first two digits of a local number were always in the range 2–9. the third digit could be any digit.

area code can be 602 but not 134 as first digit should be 2-9 and the second digit should be 0 or 1. So the number of possible area codes were 8 X 2 X 10 = 160.

Similarly for first 3 digits - we have 8 X 8 X 10 = 640 possibilities.

Explanation:

from the information given in the question that area code should start with digit  range of digit 2 to 9 and 0 and 1 may be as second digit, while third digit can be any digit. Therefore we have

Take an example -  area code can be 602 but not 134 as first digit should be 2-9 and the second digit should be 0 or 1. So the number of possible area codes were 8 X 2 X 10 = 160.

Similarly for first 3 digits - we have 8 X 8 X 10 = 640 possibilities.

you can not change you age soon as you signed up. the only way is too delete your account and use another account to sign up and put your correct age.

the file button then you go to insert tab and click insert hyperlink.