Question

Calculate the time taken by a train travelling at a speed of 300km/h to cover a distance of 1000km​

Answer 1

Answer:

25

Explanation:

Let x km/hr be the constant speed of the train,

Then Time taken to cover 300km=

x

300

hrs

Time taken to cover 300km when the speed is increased by 5km/hr=

x+5

300

hours

It is given that the time to cover 300km is reduced by 2 hours

∴

x

300

−

x+5

300

=2

⇒

x(x+5)

300(x+5)−300x

=2⇒2x

2

+10x=1500

⇒x

2

+5x−750=0⇒x

2

+30x−25x−750=0

⇒(x+30)(x−25)=0⇒x=25orx=−30

But x cannot be negative. Therefore x=25

Hence, the original speed of the train is 25km/hr

Answer 2

time = distance/speed

so, time = 1000km/300km/h

so time = 3.33 h