Given: The average speed of train = 40 km/hr
If the average speed is 35 km/hr then it is delayed by 15 minutes.
Formula Used: Time = Distance/Speed
Calculation: Let the distance of total journey be ‘d’ km.
Case 1st : Given, with an average speed of 40 km/hr, a train reaches its destination in time.
Speed = 40 km/hr, Time = d/40 hr
This is the time actually required for the journey.
Case 2nd : Given, with an average speed of 35 km/hr, it is late by 15 minutes.
Speed = 35 km/hr, Time
= As he is late by 15 minutes, the actual time for journey
=(−)hr Actual time of journey should be same.
⇒
=– ⇒=– ⇒= ⇒ d = 70 km
∴ The required distance is 70 km.