Answer: 100.8 kilometers per hour
Work Shown
total distance = 4.2 km +4.2 km = 8.4 km
total time = 3 min + 2 min = 5 min = 5/60 = 1/12 of an hour
speed = distance/time
speed = (8.4 km)/( 1/12 of an hour )
speed = 8.4*12 kilometers per hour
speed = 100.8 kilometers per hour
Extra info: This converts to approximately 62.634 mph.