Two cars X and Y start from two places A and B respectively which are 800 km apart at 8 a.m. Both the cars run at an average speed of 50 km/hr towards each other. Car X stops at 9 a.m. and again starts at 10 a.m. While the other car Y continues to run without stopping. When do the two cars cross each other?
Till 10 a.m. Dist. Covered by X = 50 km and Till 10 a.m. Dist. Covered by Y = 100 km Remaining distance to be covered at 11 a.m. = 800 – 150 = 650 km Relative speed of X and Y = 100 Km / hr ∴ Time taken = 650/100 =13/2 hrs. = 6 hrs. 30 min. ∴ Two cars will cross each other at 4.30 p.m.