Question

A car travels at a speed of 50 km/hr for 30
minutes, at 30 km/hr for next 15 minutes
and then 70 km/hr for next 45 minutes.
What is the average speed of the car?
[Ans: 56.66 km/hr]​

Answer 1

Answer:average velocity=2v1v2/2=2*60+40/60+40=2400*2/100=24*2=48

Explanation:

Answer 2

Answer:

Case 1: Speed = 50km/h

time taken = 30 min = 30/60h = 0.5h

Distance (D1) = Speed × time

=> D1 = 50km/h × 0.5h

=> D1 = 25 km

Case 2: Speed= 30km/h

time taken = 15 min = 15/60h = 0.25h

Distance (D2) = Speed × time

=> D2 = 30km/h × 0.25h

=> D2 = 7.5 km

Case 3: Speed = 70km/h

time taken = 30 min = 45/60h = 0.75h

Distance (D3) = Speed × time

=> D3 = 70km/h × 0.75h

=> D3 = 52.5 km

Total distance = D1 + D2 + D3

=>(25 + 7.5 + 52.5)km = 85 km

Total time = (0.5 + 0.25 + 0.75)h = 1.5 h

Avg Speed = Total distance/total time

=> 85 km/ 1.5 h

=> 56.66 km/h