Reactant $A$ decomposes to products $B$ and $C$ in the presence of an enzyme in a well-stirred batch reactor. The kinetic rate expression is given by$$-r_A = \dfrac{0.01C_A}{0.05+C_A} (\text{mol L}^{-1} \text{ min}^{-1})$$If the initial concentration of $A$ is $0.02 \text{ mol L}^{-1}$, the time taken to achieve $50\%$ conversion of $A$ is __________$\text{min}$ (round off to $2$ decimal places).