A cylindrical vessel of radius 4 cm contains water . A solid sphere of radius 3 cm is dipped into the water until it is completely immersed . The water level in the vessel will rise by
In a row of boys, Rahul is 19th from top and Ajay is 21st from bottom. They interchange their position. Ajay now becomes 28th from bottom. Howmany total boys are there in the row?