An ice berg of density 900 Kg/m³ is floating in water of density 1000 Kg/m³. The percentage of volume of ice-cube outside the water is

Let the total volume of ice-berg is V and its density is $\rho$. If this ice-berg floats in water with volume V_in  inside it then ${\mathrm{V}}_{\mathrm{in}}\mathrm{\sigma g}=\mathrm{V\rho g}\Rightarrow {\mathrm{V}}_{\mathrm{in}}=\left(\frac{\mathrm{\rho }}{\mathrm{\sigma }}\right)\mathrm{V}$

$\begin{array}{l}\text{ or }{\mathrm{V}}_{\text{out }}=\mathrm{V}-{\mathrm{V}}_{\mathrm{in}}=\left(\frac{\mathrm{\sigma }-\mathrm{\rho }}{\mathrm{\sigma }}\right)\mathrm{V}\\ \Rightarrow \frac{{\mathrm{V}}_{\text{out }}}{\mathrm{V}}=\left(\frac{\mathrm{\sigma }-\mathrm{\rho }}{\mathrm{\sigma }}\right)=\frac{1000-900}{1000}=\frac{1}{10}\\ \therefore {\mathrm{V}}_{\text{out }}=10\mathrm{\%}\text{ of }\mathrm{V}\end{array}$