JEE Mains Model Paper 21

A boy of mass 60 kg is standing over a platform of mass 40 kg placed over a smooth horizontal surface. He throw s a stone of mass 1 kg with velocity u = 10 m/s at an angle of with respect to ground. The displacement of platform (with boy) on the horizontalsurface, when the stone land on the ground is (g = 10 m/s2)