Question

With an average speed of 40 km/hr, a train reaches its destination in time. If it goes with an average speed of 35 km/hr, it is late by 15 minutes. Find the length of the total journey?

Answer 1

Hey.


Here is your answer.


Let the length of the total journey be x km.


Then with average velocity of 40 km/hr

it will take a time of

t1 = x / 40 hr



Also with an average velocity of 35 km/hr

it will take a time of

t2 = x / 35 hr


According to the question,

t2 - t1 = 15 minutes = 15/60 hr = 0.25 hr


so, x/35 - x/40 = 0.25

or, 40x - 35x = 40×35×0.25

or, 5x = 40×35×0.25

so, x = 40×7×0.25 = 70 km


So, the length of the total journey will be 70km.


Thanks

Answer 2

Heya....

===== Answer ====

Let the total lenght of journey = x

Average velocity = 40 km/hr
Time taken = X/40 hrs
Average velocity = 35 km/hrs
t2 = X/35 hrs

Sol :- T2 - T1

= 15 min = 15/16 hrs = 0.25 hrs

x/35 - X/40 = 0.25

= 70 km

So... 70 is the ans..

Thank you