The brass shell $({}_b=20\mathrm{.}9\frac{{10}^{-6}}{}C)$ is fully bonded to the steel core $(\{$:${}_S=11\mathrm{.}7\frac{{10}^{-6}}{}C).$ Determine the largest allowable increase in

temperature if the stress in the steel core is not to exceed $53$ MPa $.$

The largest allowable increase in temperature is ${?}^{-\text{d}\text{o}\text{t}\text{s}\text{.}\text{.}\text{.}\text{.}\text{.}\text{.}\text{.}\text{.}\text{.}\text{.}\text{.}}C.$