SOLUTION: A city currently has approximately 1,200,000 households. Most households have at least one fixed telephone line. A fixed telephone line number begins with a 6, followed by seven

Algebra ->  Permutations -> SOLUTION: A city currently has approximately 1,200,000 households. Most households have at least one fixed telephone line. A fixed telephone line number begins with a 6, followed by seven       Log On


   

Question 1146052: A city currently has approximately 1,200,000 households. Most households have at
least one fixed telephone line. A fixed telephone line number begins with a 6,
followed by seven digits that can be between 0 and 9. What is the maximum
number of unique fixed telephone lines?
Found 2 solutions by Edwin McCravy, richwmiller:
Answer by Edwin McCravy(20064) About Me  (Show Source):
You can put this solution on YOUR website!

 Since the counting numbers       1 through the 7-digit number 
                            9999999, inclusive, account for 
                            9999999 counting numbers, the 8-digit phone numbers
                           60000001 through 
                           69999999 similarly account for that same number,
                            9999999, of phone numbers, plus the one phone number 
                           60000000, so there are 
                           10000000 phone numbers. 
That's ten million.

Edwin

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
This must be a very old problem. Very few people maintain a fixed landline anymore. Business do but not homes. And I was told that ATT doesn't install them anymore.
I believe the 555 exchange (ie 555-0000 to 555-9999) is reserved for TV and movie numbers. They are not given out.