If a person travels 2/5th of a distance at 20 km/h, 1/5th of the distance at 30 km/h and rest of the journey at 40 km/h, then what is his average speed for the entire journey?
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Let the total distance of the journey be d.
The person travels 2d/5 distance with speed 20km/hr, ie, he takes (2d/5) /20 hours (= 8d hours) to travel that distance.
Similarly he travels d/5 distance in 6d hours.
Now, rest of the journey is of 2d/5 km which he travels at a speed of 40km/hr.
He travels that distance in time = (2d/5)/40
= 16d km
{Using time = distance/ speed}
Now, the average speed = total distance/ total time
avg speed = d/(8d+6d+16d)
= d/(30d)
= 1/30 km/hr
That's it! I hope you understand the concept. You just need to calculate the time taken for traveling in all separate parts of the journey and calculate the total time.
All the best! Practice more, you will understand it definitely.
Please mark it as brainliest if you find it helpful.
The person travels 2d/5 distance with speed 20km/hr, ie, he takes (2d/5) /20 hours (= 8d hours) to travel that distance.
Similarly he travels d/5 distance in 6d hours.
Now, rest of the journey is of 2d/5 km which he travels at a speed of 40km/hr.
He travels that distance in time = (2d/5)/40
= 16d km
{Using time = distance/ speed}
Now, the average speed = total distance/ total time
avg speed = d/(8d+6d+16d)
= d/(30d)
= 1/30 km/hr
That's it! I hope you understand the concept. You just need to calculate the time taken for traveling in all separate parts of the journey and calculate the total time.
All the best! Practice more, you will understand it definitely.
Please mark it as brainliest if you find it helpful.
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