Question

On a 60 km straight road , a bus travels the first 30 km with a uniform speed of 30 kmh-1 . how fast must the bys travel the next 30 km so as to have average speed of 40 kmh-1 for the entire trip ?

Answer 1

thanks for your question and it is your answer

Answer 2

Hi..

Given:

Total distance =60km

Average speed of entire journey=40km/h

Total Time taken =
total distance/average speed

=60/40

=3/2hr

Case 1 :

Time taken to cover first 30km

Speed=30km/h

Distance=30km

T=distance/ speed=30/30

=1hr -----equation ( 1)

Case: 2

Time taken to travel next 30km

Let speed be =Xkm/ h

X=30KM/t

t=30/X hours ----equation( 2)

Total time =1 +30/X

Since total time =3/2 hr

3/2 =1 +30/X

3/2-1 =30/X

1/2 =30/X

X=60km/h

Therefore bus should travel next 30km distance at a speed of 60 km/h.


Hope this helps u!!