A boy goes from A to B with a velocity of 20 m/min and comes back from...
Solution:
Given:
- Velocity of the boy from A to B = 20 m/min
- Velocity of the boy from B to A = 30 m/min
To Find:
Average velocity of the boy during the whole journey.
Formula:
If an object travels a distance d1 with velocity v1 and then travels a distance d2 with velocity v2, then the total distance travelled is d1 + d2 and the average velocity of the object is given by:
Average Velocity = (d1 + d2) / (t1 + t2)
where t1 and t2 are the time taken to travel d1 and d2 distances respectively.
Explanation:
Let the distance between A and B be d.
So, the time taken by the boy to travel from A to B = d / 20
Similarly, the time taken by the boy to travel from B to A = d / 30
Therefore, the total time taken by the boy to travel the whole distance = (d / 20) + (d / 30) = (3d + 2d) / 60 = 5d / 60 = d / 12
Now, the total distance travelled by the boy = d + d = 2d
Using the formula mentioned above, we get:
Average Velocity = (2d) / (d / 12 + d / 12) = 24d / d = 24 m/min
Answer:
Therefore, the average velocity of the boy during the whole journey is 24 m/min.