==> \({P_1}{V_1} = {P_2}{V_2}\)

==> \(({P_0} + h{\rho _w}g){V_1} = {P_0}{V_2}\)\( \Rightarrow {V_2} = \left( {1 + \frac{{h{\rho _w}g}}{{{P_0}}}} \right){V_1}\)

==> \({V_2} = \left( {1 + \frac{{47.6 \times {{10}^2} \times 1 \times 1000}}{{70 \times 13.6 \times 1000}}} \right)\,{V_1}\) [\({P_2} = {P_0} = 70\,cm\) of Hg \( = 70 \times 13.6 \times 1000\)]

\( \Rightarrow {V_2} = (1 + 5)50\,c{m^3} = 300\,c{m^3}.\)