A non-isotropic solid metal cube has coefficients of linear expansion as: $5\times {10}^{-5}/{}^{\text{o}}\text{C}$ along the x-axis and $5\times {10}^{-6}/{}^{\text{o}}\text{C}$ along the y and the z-axis. If the coefficient of volume expansion of the solid is $\text{C}\times {10}^{-6}/{}^{\text{o}}\text{C}$ then the value of $\mathrm{C}$ is _____________