A body is deformed continuously in a machine press. The density
\(\rho \) is inversely proportional
to the volume \(V \) of the body,
i.e. there exists a constant \(k\)
such that
\[
\rho = \frac{k}
{V }.
\]
Find the constant \(k\)
(including the correct unit) if it is known that the density was
\(\rho = 25\: \frac{\mathrm{kg}}
{\mathrm{m}^{3}} \) when the body
had volume \(V = 2\, \mathrm{dm}^{3}\).