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A car that travels on a hill covered 1/2 part of its covered distance at 30 km/hr, 1/3 part of its covered distance at 20 km/hr and the remaining distance at 10 km/hr. Find the average speed of the car in the whole journey?

A car that travels on a hill covered 1/2 part of its covered distance at 30 km/hr, 1/3 part of its covered distance at 20 km/hr and the remaining distance at 10 km/hr. Find the average speed of the car in the whole journey? Correct Answer 20 km/hr

Given:

1/2 part covered with speed = 30 km/h

1/3 part covered with speed = 20 km/h

Remaining covered with speed = 10 km/h

Formula used:

Speed = Distance/Time

Average speed = Total distance/Total time

Calculation:

Let the total distance be 60 km

Time taken by the car to cover (1/2 part of 60) 30 km = 30/30 = 1 hr

Similarly, time taken by the car to cover (1/3 part of 60) 20 km

= 20/20 = 1 hr

Remaining distance = 60 - 20 - 30 = 10 km

Similarly, time taken by the car to cover remaining distance

= 10/10 = 1 hr

So, average speed = 60/(1 + 1 + 1) = 60/3 = 20 km/hr

∴ The average speed of the journey is 20 km/h

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