For a given chemical reaction γ_1 A+γ_2 B → γ_3 C+γ_4 D Concentration of C changes from 10 mmol dm^-3 to 20 mmol dm^-3 in 10 seconds. Rate of…

For a given chemical reaction $$\gamma_1 A+\gamma_2 B \rightarrow \gamma_3 C+\gamma_4 D $$ Concentration of C changes from $\displaystyle 10 \mathrm{mmol} \mathrm{dm}^{-3}$ to $\displaystyle 20 \mathrm{mmol} \mathrm{dm}^{-3}$ in $\displaystyle 10$ seconds. Rate of appearance of $\displaystyle D$ is $\displaystyle 1.5$ times the rate of disappearance of $\displaystyle B$ which is twice the rate of disappearance A. The rate of appearance of D has been experimentally determined to be $\displaystyle 9 \mathrm{mmol} \mathrm{dm}^{-3} \mathrm{~s}^{-1}$. Therefore the rate of reaction is \_\_\_\_ $\displaystyle \mathrm{mmol} \mathrm{dm}^{-3} \mathrm{~s}^{-1}$. (Nearest Integer)