A passenger plane flew from NY city to Los Angeles non-stop in 5 equal distances at the following average speeds for each distance: 600 km/h, 750 km/h, 800 km/h, 650 km/h and 825 km/h. What was the average speed of the plane from NY to LA? Thank you.
+9674 Let each "equal distance" as L.
The time taken for each "equal distance" is calculated by time = (distance)/(speed) = \(\dfrac L{600}, \dfrac L{750}, \cdots, \dfrac L{825}\).
Average speed = (distance)/(time) = \(\dfrac{5L}{\dfrac L{600} + \dfrac L{750} + \dfrac L{800} + \dfrac L{650} + \dfrac L{825}} = \dfrac 5{\dfrac1{600} + \dfrac 1{750} + \dfrac1{800} + \dfrac1{650} + \dfrac1{825}}\).
Now you can use a calculator to get the required average speed.
