An open rectangular custern when measured outside is $1.35\;m$ long $1.08\;m$ broad and $90\;cm$ deep and is made of iron which is $2.5\;cm$ thick . Find the capacity of the custern and the volume of the iron used

Question

$\begin{array}{1 1} 6400\;cm^3 \\ 140575\;cm^3 \\ 634500\;cm^3 \\ 6300\;cm^3 \end{array} $