Question
Bala travels first one-third of the total distance at
the speed of 10 km/h and the next one-third distance at the speed of 20 km/h and the last one – third distance at the speed of 60 km/h. What is the average speed of Bala?Solution
ATQ, we can say that Let the total distance be 180 km. 1/3rd of total distance = 180 × (1/3) = 60 km Time taken by Bala to cover first one-third of the total distance = 60/10 = 6 hrs Time taken by Bala to cover next one-third of the total distance = 60/20 = 3 hrs Time taken by Bala to cover last one-third of the total distance = 60/60 = 1 hr Average speed = Total time/total distance = 180/ (6 + 3 + 1) = 180/10 = 18 km/hr.
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