You are provided with a hollow iron ball of volume 20 cm3, a mass of 15 g and a solid iron ball of mass 20 g. Both are placed on the surface of water contained in a large tub. Which will float? Give reason for your answer

The hollow iron ball will float since its average density is 15 g/20 cm3 = 0.75 g cm-3 which is less than the density of water (1 g cm-3), whereas the solid iron ball will sink since its density is 8.9 g cm-3 which is more than that of water.

Sir can you explain that why is theanswer become8.9g cm-3