Question

Please Answer the question

A car travels at a speed of 90 km/h during the first half of its running time and at 50 km/h during the other half. Find the average speed of the car.​

Answer 1

Solution:

Speed of car during first half(v₁) = 90km/h

Speed of car during second half(v₂) = 50km/h

Total Time taken by a car = 2t

Total Distance covered by a car = 90t+50t = 140t

Average speed = Total Distance/Total Time

Average speed = 140t/2t = 70km/h.

Answer 2

$\huge\mathbb\pink{Solution}$

Let the each half of the running time be t .

During first half time, speed of car is 90 km/h

$Distance \: covered   d_{1} =90t km$

During first half time, speed of car is 50 km/h$Distance \: covered \: d_{2} = 50t \: km$

$Total \: distance \: covered   \: d =d1+d2 \\ =90t+50t \\ =140t$

Total time taken T=2t$Average \: speed    v_{avg} = \frac{d}{t} \\ = \frac{140t}{2t} \\ =70 km/hr$