A person covers 48 km at the speed of 8 km/h, 36 km at the speed of 18 km/h and 16 km at the speed of 8 km/h. What is his average speed in covering the whole distance?
10 km/h
The correct answer is 10 km/h.
However, if an object covers the same distance at different speeds, the average speed is the harmonic mean of the speeds. In this problem, the distances are different across the different speed segments, so the general formula (Total Distance / Total Time) must be used. Always remember to use the total distance and total time when calculating average speed over a journey with varying speeds.
Similar Questions
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Important Questions from Average Speed
Kapil travels for 4.5 hours at a speed of 50 km / h and 7.5 hours at a speed of 70 km / h. At the end of it, he finds that he covered only 6/7 of the total distance. At what average speed should he travel so that the remaining distance traveled in 5 hours?
A car has to cover 125 kms in 5 hours. What will be the average speed of the car if it has covered 90 kms in the first 3 hours?
A scooter from P to Q travels at 40 km/h and from Q to P at 30 km/h. What is the average speed of the scooter?
To cover a distance of 144 km in 3.2 hours what should be the average speed of the car in meters/second?
A cylindrical road roller having a diameter of 1.5 m moves at a speed of 3km/h while levelling a road. How much length of the road will be levelled in 45 minutes?
