Question

A car covers the first half of the distance between two places at a speed of 40km/ h and the second half at 60 km/h.what is the average speed of the car?​

Answer 1

Answer:

Let us assume the total distance to be x.

The time taken by the car to cover the first half distance with the speed of 40 km/hr = t_1.

The time taken by the car to cover the second half distance with the speed of 60 km/hr = t_2.

Now, We know that, Speed = Distance/Time.

Hence, Time = Distance/Speed.

So, t_1 = x/2*40 = x/80 s

And, t_2 = x/2*60 = x/120 s

Now, Total time taken = t_1 + t_2 = x/80 + x/120

⇒ Total time = (120x + 80x)/120*80

⇒ Total time = 200x/9,600

⇒ Total time = 2x/9,6

⇒ Total time = x/48 seconds

Now, Average Speed = Total Distance/Total Time

⇒ Avg. speed = x/(x/48)

⇒ Avg. speed = x*48/x

⇒ Avg. speed = 48 km/hr.

Hence, The Average Speed of the car = 48 km/hr.