Question

How many different phone numbers are possible in the area code 503, if the first number cannot start with a 0 or 1

Answer 1

Answer:

8 X 10^(9)

Step-by-step explanation:

Originally we have 10 digit phone numbers excluding the area code.

For each face value we have these in store: 0,1,2,3,4,5,6,7,8,9 (total 10)

But if we exclude 1 and 0 for the first digit, we are left with 8 digits.

8P1 X .......

In a phone number, digits can repeat so we can choose out of these 10 numbers freely after this.

8P1 X 10P1 X 10P1 X...

Adding the area code while assuming 10P1 is just 10...we get:

1 X 1 X 1 X 8 X 10^(9)

= 8000000000

Very interesting question, thanks for the opportunity!

Answer 2

Answer:

8000000

Step-by-step explanation:

503-xxx-xxxx

for the last 7 digit: 2-9 .... 8 for first digit

                              0-9 .... 10 for digit 2 to digit 7

Total: 8*10*10*10*10*10*10 = 8000000