Average speed = Total distance ÷ Total time.<br><br>
&bull; Time for 40 km at 80 km/h: 40 ÷ 80 = 0.5 h<br>
&bull; Time for 45 km at 60 km/h: 45 ÷ 60 = 0.75 h<br>
&bull; Total distance = 40 + 45 = 85 km<br>
&bull; Total time = 0.5 + 0.75 = 1.25 h<br>
&bull; Average speed = 85 ÷ 1.25 = 68 km/h<br><br>
Final Answer: 68 km/h