2002 AMC 12A Problem 11
Problem 11 of 25IntermediateAlgebra
Mr. Earl E. Bird leaves his house for work at exactly A.M. every morning. When he averages miles per hour, he arrives at his workplace three minutes late. When he averages miles per hour, he arrives three minutes early. At what average speed, in miles per hour, should Mr. Bird drive to arrive at his workplace precisely on time?
Answer choices
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Solution
Let be the time in hours to arrive on time. Since three minutes is hours,
This gives so The distance is miles, and the required speed is miles per hour.
Thus, the correct answer is B.