A car travels from A to B at a speed of 20 km h_1and returns at a speed of 30 km h_1. The average speed of the car for the whole journey isa)5 km h_1b)24 km h_1c)25 km h_1d)50 km h_1Correct answer is option 'B'. Can you explain this answer?

Question

Answer

Given v1=20km/hr.....v2=30km/hr....->> Average speed (v)=2v1v2/v1+v2 v=24km/hrThis might be useful for you: 'Motion - Motion in a Straight Line, Class 11, Physics '

Motion - Motion in a Straight Line, Class 11, Physics

https://edurev.in/studytube/motion-motion-in-a-straight-line--class-11--physic/086ff6cd-37b4-4ee9-b146-8de262907385_t

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Answer

Answer

Use total distance covered by total time taken .. B is ryt

Answer

(v1+v2)/2

Answer

To find the average speed of the car for the whole journey, we can use the formula:

Average speed = Total distance / Total time

Let's assume the distance from A to B is 'd' kilometers. Since the car travels from A to B at a speed of 20 km/h, the time taken to cover this distance is:

Time taken to go from A to B = d / 20

Similarly, when the car returns from B to A at a speed of 30 km/h, the time taken is:

Time taken to return from B to A = d / 30

Now, to find the total time taken for the whole journey, we need to add the time taken to go from A to B and the time taken to return from B to A:

Total time = (d / 20) + (d / 30)

Simplifying this expression, we get:

Total time = (3d + 2d) / 60
Total time = 5d / 60
Total time = d / 12

Since we know that Average speed = Total distance / Total time, we can substitute the value of Total time in the above equation:

Average speed = d / (d / 12)
Average speed = d * (12 / d)
Average speed = 12 km/h

Therefore, the average speed of the car for the whole journey is 12 km/h.

However, none of the given options match this answer. So, it seems there is an error in the question or answer choices provided.

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