A block of ice of density $0.9\text{gm}{\text{cc}}^{-1}$ and of volume $100\text{cc}$ floats in water. Then volume of ice inside the water

Volume V = 100 c.c

Block of ice floats in water 9 out of 10 parts of its volume

Volume of ice inside water$=\text{100 c}\text{.c}-\text{10 c}\text{.c}=\text{90}\text{c}\text{.c}$