Consider the following reaction, the rate expression of which is given below
$ \begin{aligned} & \mathrm{A}+\mathrm{B} \rightarrow \mathrm{C} \\ & \text { rate }=\mathrm{k}[\mathrm{~A}]^{1 / 2}[\mathrm{~B}]^{1 / 2} \end{aligned} $
The reaction is initiated by taking 1 M concentration A and B each. If the rate constant ( k ) is $4.6 \times 10^{-2}
\mathrm{~s}^{-1}$, then the time taken for A to become 0.1 M is $\_\_\_\_$ sec. (nearest integer)