Question

A car travels 30 km at a uniform speed of 40 km/h and next 30 km at a uniform speed of 20 km/h. Its average speed is

Answer 1

given that ,    

1st 30 km uniform speed is (u1) = 40 km/h    

 2nd 30 km uniform speed is ( u2 ) = 20 km/h

    total distance ( d ) = 30 + 30 = 60 km    

time taken in 1st time = d / t = 30/40 also, 3h / 4 = 180/4 = 45 min    

tim taken in 2nd time = d/t = 30/20 also, 3h/2 = 180/2 = 90 min    

total time = 45 + 90 = 135 min = 135/60 h

av.speed = 60/135/60 = 60 * 60 /135 = 26.66 km/h ( answer )        

Answer 2

hlw

17/12km/hr is their average speed which literally means
1.415km/hr is their average speed