SOLUTION: Telephone numbers in the US start with a 3 digit area code followed by a 7 digit local number. Assume that any number (0-9) is possible for each digit. a) How many different ar

Question 878785: Telephone numbers in the US start with a 3 digit area code followed by a 7 digit local number. Assume that any number (0-9) is possible for each digit.
a) How many different area codes are possible?
b) What is the probability that an area code starts with a 5?
c) For a given area code, how many different local numbers are possible?
d) How many different complete telephone numbers are possible?

Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
Telephone numbers in the US start with a 3 digit area code followed by a 7 digit local number. Assume that any number (0-9) is possible for each digit.
a) How many different area codes are possible?
3 decimal digits. What do you think?
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b) What is the probability that an area code starts with a 5?
5 is 1 of 10 possibilities.
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c) For a given area code, how many different local numbers are possible?
7 decimal digits.
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d) How many different complete telephone numbers are possible?
10 decimal digits -->

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