A train covered a certain distance at a uniform speed. If the train would have been 6km/hr. faster, it would have taken 4 hours less than the scheduled time. And if the train were slower by 6km/hr. it would have taken 6 hours more than the scheduled time. Find the length of the journey.

let the speed of the train = x km/hr

let the distance covered = y km.

scheduled time to cover the distance = distance / speed

= y / x hr

if the train is 6 km / hr faster, new speed = (x+6) km/hr

it would have taken 4 hr less, therefore

if the train were 6 km / hr slower, new speed = (x-6) km / hr

it would have taken 6 hrs more, therefore

substituting the value of y in terms of x , from eq(2) to eq(1):

since x is the speed of the train therefore x =30 km / hr

and substitute x = 30 in eq(2):

thus the distance covered is 720 km and speed of the train is 30 km / hr.

hope this helps you.

cheers!!

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