\({\left( {\frac{{\Delta q}}{{\Delta t}}} \right)_1} = {\left( {\frac{{\Delta q}}{{\Delta t}}} \right)_2}\)
\(\frac{{3mkA\left( {{\theta _2} - \theta } \right)}}{d} = \frac{{kA\left( {\theta - {\theta _1}} \right)}}{{3d}}\)
\( \Rightarrow \,\,\theta = \frac{{{\theta _1} + 9{\theta _2}}}{{10}}\)