X and Y are two stations which are 280 km apart. A train starts at a certain time from X and travels towards Y at 60 km/h. After 2 hours, another train starts from Y and travels towards X at 20 km/h. After how many hours does the train leaving from X meets the train which left from Y?

4 hours

Formula used :-

Distance = Speed × Time

Distance covered by first train in 2 hr = 60 × 2 = 120 km

Remaining distance = 280 - 120 = 160 km

Relative speed ( when moves in  opposite direction ) = 60 + 20 = 80 km/hr

Time when both train meet = \(\frac{160}{80}\) = 2 hours

Total time when they meet = 2  + 2  = 4 hours