Solved: Joe started a phone tree to give information about a party to his friends. Joe
Chapter 0, Problem 34(choose chapter or problem)
Joe started a phone tree to give information about a party to his friends. Joe starts by calling 3 people. Then each of those 3 people calls 3 people, and each person who receives a call then calls 3 more people. How many people have been called after 4 layers of the phone tree? (Hint: Joe is considered the first layer.)
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