Question

If an object covers half of the distance with speed 60m/s for remaining half it covers half of the total time with speed 20m/s and the remaining half of the time it's speed was 40m/s,then find its average speed​

Answer 1

Correct option is

B

24 m/s

Let the total distance be 2x.

For first half distance :

Speed is 20 m/s

Thus time taken t

1

=

20

x

For second half distance :

Speed is 30 m/s

Thus time taken t

2

=

30

x

Average velocity V

avg

=

t

1

+t

2

2x

⟹ V

avg

=

20

x

+

30

x

2x

=

20+30

2×20×30

=24 m/s