a. If any seven digits could be used to form a telephone
Chapter 9, Problem 16E(choose chapter or problem)
a. If any seven digits could be used to form a telephone number, how many seven-digit telephone numbers would not have any repeated digits?b. How many seven-digit telephone numbers would have at least one repeated digit?c. What is the probability that a randomly chosen seven-digit telephone number would have at least one repeated digit?
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