Answer
The mass density: $\delta \left( {x,y,z} \right) = 5$ $kg/{m^3}$
Work Step by Step
We have a solid region of volume $V=5$ ${m^3}$ with uniform mass density and total mass $M=25$ kg.
The mass density $\delta \left( {x,y,z} \right)$ is
$\delta \left( {x,y,z} \right) = \frac{M}{V} = \frac{{25}}{5} = 5$ $kg/{m^3}$
