Sloan the sloth crawls at 100 meters per hour when crawling uphill, 120 meters per hour when crawling across flat ground, and 150 meters per hour when crawling downhill. One day, Sloan crawls across the forest floor from a tree stump to a spring, and then takes the same route in reverse to return to the tree stump. What was Sloan's average speed during the entire round trip?
120 m/s answered the other day
We know the average flat speed is 120
If you draw a diagram you will see that the up and the down paths are equal for his roundtrip
Call the distance one way = d 2 d for round trip
time on uphill d/100 time on downhill d/150
average speed 2 d /(d/100+d/150) = 2d/ ( 3d/300 + 2d/300) = 2d / ( 5d/300) = 600/5 = 120 m/s
so all of the sections average 120 m/s so his overall average speed is 120 m/s