GIVEN: Two trains a superfast express and a passenger train having lengths 580 m and 470 m are travelling towards each other with the speeds of 80 km/h and 46 km/h respectively. FORMULA USED: Time = Distance/Speed Relative speed if running in opposite directions = Sum of speeds CALCULATION: We can observe: Relative speed of the trains = 80 + 46 = 126 km/h = 126 × (5/18) = 35 m/s And Total distance of be covered from crossing =580+470=1050 m ∴ Time taken to cross each other =