Given: Train A starts at 9 am at speed 70 km / hr Train B starts at 11 am at speed 20 km / hr Distance between two stations 320 km Formula Used: When the two objects travel in the same direction their relative speed = (a – b) km / hr When the two objects travel in the opposite direction their relative speed = (a + b) km / hr Where a and b are speeds of two objects in km / hr and (a > b) Speed = Distance / Time Calculation: Distance covered by train A in 1st two hours = Speed × time ⇒ 70 km / hr × 2 = 140 kms Remaining Distance = 320 km – 140 km = 180 km From 11 am train B also start running at speed of 20 km / hr ∴ Relative speed of both the trains = (70 km / hr + 20 km / hr) = 90 km / hr Time taken = Distance / speed ⇒ 180 / 90 = 2 hrs ∴ Both the trains meet at 1 pm