Question

1) A bag contains X white, Y red and Z blue . A ball is drawn at random , then find the probability of drawing a blue ball ?

Answer 1

$$\begin{gathered} \mathrm{Number}\mathrm{of}\mathrm{white}\mathrm{balls}=x \\ \mathrm{Number}\mathrm{of}\mathrm{red}\mathrm{balls}=y \\ \mathrm{Number}\mathrm{of}\mathrm{blue}\mathrm{balls}=z \\ \mathrm{Total}\mathrm{number}\mathrm{of}\mathrm{balls}=x+y+z \\ \mathrm{Total}\mathrm{possible}\mathrm{outcomes}=x+y+z \\ \mathrm{Number}\mathrm{of}\mathrm{blue}\mathrm{balls}=z \\ \mathrm{Number}\mathrm{of}\mathrm{favourable}\mathrm{outcomes}=z \\ \mathrm{P}\left(\mathrm{blue}\mathrm{ball}\right)=\frac{\mathrm{Number}\mathrm{of}\mathrm{favourable}\mathrm{outcomes}}{\mathrm{Total}\mathrm{possible}\mathrm{outcomes}}=\frac{z}{x+y+z} \end{gathered}$$