a person goes up a hill on a cycle with the speed 10 km per hour and comes down with the speed 40 km per hour whats his average speed.(total distance and time is not given)
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Answers
A cyclist moves uphill at a constant speed of v1 = 10 km/h. When he reaches the top of the hill, he turns and passes the same track downhill at a speed of v2 = 40 km/h. What is the average speed of a cyclist?
To correctly figure out the average speed based on distance traveled, you have to take the inverse of speed, convert km/h to h/km.
The inverse of 10 km/h is .1 h/km.
The inverse of 40 km/h is .025 h/km
Now we take the average of .025 and .1 h/km and it is .125/2 or .0625 h/km.
Now we invert .0625 to go from h/km to km/h and that would be 16 km/hour.
Now you understand why bicycle racers stand on the pedals and pump at maximum effort while climbing a hill but frequently coast and catch their wind while going downhill.
Now if you changed the question to what is the average speed of a bicycle that goes 10 km/h for one hour and 40 km/h for another hour, then the average speed would be 25 km/h, but the lion’s share of the total DISTANCE traveled would be at the higher speed.
When the distances covered are equal at these two speeds, the lion’s share of the TIME is consumed on the uphill.