Question

A car travels a certain distance with a speed of 60kmh and returns with a speed of 50kmh. find the avg speed

Answer 1

let the car travels a distance x km at 50 km/h. 
=> x/50 hours. 
as car travels the same distance x km at 40 km/h. 
=> x/40 hours. 
Total distance= 2x km 
Total time= x/50 + x/40 hs 
Avg speed = Total dist. / Total time
=> 2x / (x/50 + x/40)  
=> 2 * 50 * 40 / (50 + 40)
=> 44.4 km/h