Average Speed = Total Distance &divide; Total Time.<br><br>&bull; Total rounds = 4, each 400 m &rarr; Total distance = 4 &times; 400 = 1600 m<br>&bull; Total time = 13.5 min + 6.5 min = 20 min<br>&bull; Average speed = 1600 m &divide; 20 min = 80 m/min<br><br>Final Answer: 80 m/min