In Scenario 1. I travel 1000 KMs @ 100 KM/Hr. I reach my destination in 10 Hours. In Scenario 2. I travel 600 KMs @ 80 KM/Hr. I reach my destination in 7.5 Hours. How much time do I save due to reduction in distance and how much time is wasted due to reduction in speed? If I do not change the speed but only change distance (600 KM, 100 KM/Hr), I get 4 hours saved. If I do not change the distance but only the speed (1000KM, 80 KM/Hr), I get 2.5 hours extra. -4 + 2.5 = -1.5. However, in total, I have saved 2.5 hours. So how do I find the contribution of distance and speed in my overall time savings?