elastic limit of a typical rock is 30.10 and its dencity =3 into 10 raise to3 explain height of a mountain cannot exceed 10km?

Dear Student,

The values provided doesnt have any unit. 

But in a general solution.

A mountain is approximately a conical body.

$$\begin{gathered} Thus its volume \approx R^2{H}_{max} \\ Thus its weight\approx Density\left(\rho \right)\times R^2{H}_{max}\times g \\ Now when you say elastic limit, it basically tells you about the limiting stress a material \\ can withs\tan d beyond which it crumples. \\ Area of the base is of the order of\approx R^2 \\ Thus Stress=\frac{Weight}{Area}\Rightarrow \frac{\rho g{R}^2{H}_{max}}{R^2}\Rightarrow \rho g{H}_{max} \\ Let breaking stress i.e elastic limit be denoted by S_{Breaking} \\ Thus we have, \\ {S}_{Breaking}=\rho g{H}_{max} \\ or, H_{max}\approx \frac{S_{Breaking}}{\rho g} \end{gathered}$$
Regards.