Roy bought a new battery-gasoline hybrid car. On a trip the car ran exclusively on its battery for the first 40 miles, then ran exclusively on gasoline for the rest of the trip, using gasoline at a rate of 0.02 gallons per mile. On the whole trip he averaged 55 miles per gallon. How long was the trip in miles?<spanclass=′latex−bold′>(A)</span>140<spanclass=′latex−bold′>(B)</span>240<spanclass=′latex−bold′>(C)</span>440<spanclass=′latex−bold′>(D)</span>640<spanclass=′latex−bold′>(E)</span>840