An airplane travels 3900 km at 810 km/h, and then encounters a tailwind that boosts its speed to 950 km/h for the next 3000 km. What was the average speed of the plane for this trip?

Question

An airplane travels 3900 km at 810 km/h, and then encounters a tailwind that boosts its speed to 950 km/h for the next 3000 km.  What was the average speed of the plane for this trip?

3900+3000
 6900
6900/8
862.5

Damon · Answer

It goes 6900 km the time is 3900/810 + 3000/950 so Vaverage = 6900 / [ 390/81 + 300/95 ] = 865.4