Two trains start at the same time from Dehradun and Jaipur and proceed toward each other at the speed of 55 km/hr and 25 km/hr respectively. When they meet, it is found that one train has travelled 150 km more than the other. Find the distance between Dehradun and Jaipur.

Sol: Difference between speed of train from Dehradun and that of Jaipur = 30 km/hr That means train from Dehradun runs 30 km more than train from Jaipur in 1 hour. Therefore, train from Dehradun must have run 150 km more than train Jaipur in 5 hrs. That means both the trains have run for 5 hrs, when they met. Distance covered by train from Dehradun in 5 hrs = Speed × Time = 55 × 5=275 km. Distance covered by train from Jaipur in 5 hrs = Speed × Time = 25 × 5= 125 km. Total Distance between train from Dehradun and Jaipur = 275km + 125km = 400 km.