Mr. Earl E. Bird leaves his house for work at exactly 8:00 A.M. every morning. When he averages 40 miles per hour, he arrives at his workplace three minutes late. When he averages 60 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?
<spanclass=′latex−bold′>(A)</span>45<spanclass=′latex−bold′>(B)</span>48<spanclass=′latex−bold′>(C)</span>50<spanclass=′latex−bold′>(D)</span>55<spanclass=′latex−bold′>(E)</span>58