A person goes from point A to B and comes back. His average speed for the whole journey is 30 km/hr. If his speed while going from A to B is 24 km/hr.
Answers
Answer:
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