Mathematics - Probability Question with Solution | TestHub

For $k=1,2,3$ the box ${\mathrm{B}}_k$ contains $k$ red balls and $(k+1)$ white balls. Let $\mathrm{P}\left({\mathrm{B}}_1\right)=\frac{1}{2},\mathrm{P}\left({\mathrm{B}}_2\right)=\frac{1}{3}$ and $\mathrm{P}\left({\mathrm{B}}_3\right)=\frac{1}{6}.\mathrm{A}$ box is selected at random and a ball is drawn from it. If a red ball is drawn, then the probability that it has come from box ${\mathrm{B}}_2,$ is