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How Many Phone Numbers?

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Linda Vo

on 10 June 2015

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Transcript of How Many Phone Numbers?

How Many Phone Numbers?
How many 10-digit numbers are restricted in the Atlanta area?
400 numbers are restricted
Using all of the restrictions above, how many 7 digit numbers are possible in a single area code?
6,479,900 possible numbers
In 1947 when area codes were first introduced, 404 was the only area code for the entire state of Georgia. area code 912 for southern Georgia was created in 1954, and several other area codes have been added since then. Currently, the Atlanta metropolitan area uses area codes 404, 770, 678, and 470. Area code 404 is mostly in Atlanta. Area code 770 is mostly in the suburbs. Area codes 678 and 470 overlay both 404 and 770.

In the next few problems, you will estimate the number of possible telephone numbers in Georgia. You will answer these questions in a word document. Submit your assignment when finished.

Rules for telephone numbers:

A telephone number consists of seven digits, the first three representing the exchange. The first digit of an exchange cannot be 1 or 0.
The second digit and third digit cannot both equal 1 since these values are designated for other purposes such as 911 (emergency) and 411 (information).
555-0100 through 555-0199 are reserved for fictional uses such as in television shows or movies. Therefore, a total of 100 numbers are not used. For example, 555-0168 would not be a valid phone number.
How many phone numbers were possible in the state of Georgia before 1954? (disregard rules 2 and 3)
8,000,000 possible numbers
Today, how many phone numbers are possible in the Atlanta metropolitan area? (disregard rules 2 and 3)
404 -> 8,000,000
770 -> 8,000,000
678 -> 8,000,000
470 -> 8,000,000
32,000,000 possible numbers
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