Without stoppage a train travels at an average speed of 75 km per hour...
Given information:
- Average speed of the train without stoppage = 75 km/hr
- Average speed of the train with stoppage = 60 km/hr
To find:
- How many minutes per hour does the train stop?
Let's assume that the distance covered by the train is D km and the time taken to cover this distance without stoppage is T1 hours. Similarly, the time taken to cover the same distance with stoppage is T2 hours.
We know that,
- T1 = D/75 (time taken without stoppage)
- T2 = D/60 (time taken with stoppage)
We need to find the time for which the train stops. Let's assume that the train stops for 'x' minutes per hour.
To convert minutes into hours, we divide it by 60. Therefore, the time for which the train stops in hours is x/60.
Now, let's calculate the time taken by the train when it stops for 'x' minutes per hour.
- Distance covered in one hour = 75 km (without stoppage)
- Distance covered in one hour = 60 km (with stoppage)
- Distance covered in one hour = Distance covered without stoppage - Distance covered with stoppage
- 75 = (60-x/60)T1
- 60 = (60-x/60)T2
- Solving these two equations, we get x = 12 minutes.
Therefore, the train stops for 12 minutes per hour. Hence, the correct answer is option (c) 12 min.
Without stoppage a train travels at an average speed of 75 km per hour...
Answer ( C ) 12 min