city a to city b , john drove for 1 hour at 40 mph and for 3 hours at 60 mph . what was the average speed for the whole trip ?
the total distance is 1 × 40 + 3 × 60 = 220 and the total time is 4 hours . hence , average speed = ( total distance / total time ) = 220 / 4 = 55 answer : e
divide(add(multiply(1, 40), multiply(3, 60)), add(1, 3))