Chemical Kinetics

The rate for reaction \(2 \mathrm{~A}+\mathrm{B} \rightarrow\) product is \(6 \times 10^{-4} \mathrm{~mol} \mathrm{~dm}^{-3} \mathrm{~s}^{-1}\) Calculate the rate constant if the reaction is first order in \(\mathrm{A}\) and zeroth order in \(\mathrm{B}\). [Given \([\mathrm{A}]=[\mathrm{B}]=0.3 \mathrm{M}]\)