Question

a person goes somewhere with speed 20 km/h and returns back with speed 30 km/h. what is the average speed with while is moving?
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Answer 1

Answer:

Let's try to solve it in a very easier way…

Let us assume the distance between A to B is x km.

So , the car travels a total distance of (x+x) = 2x km.

Now, the car travels at a speed of 20 km/hr from A to B .

So, time taken by the car to reach at the point B from point A is given by,

Car travels 20 km in 60 minutes.

Car travels x km in (60÷20)×x minutes

= 3x minutes

Now, in the time of returning the car returns at a speed of 30 km/hr.

So, time taken by the car to reach A from B is given by,

Car travels 30 km in 60 minutes.

Car travels x km in (60÷30)×x minutes

= 2x minutes.

So , the car takes a total time of ( 3x+2x)=5x minutes.

Now , the average speed of the car for the whole journey is given by,

In 5x minutes the car covers a distance of 2x km.

So, in 60 minutes the car covers a distance of (2x÷5x)×60 km

= 24 km.

So , the average speed of the car for the whole journey is 24km/hr.

#BrainLock.