• # question_answer A jar contains 54 marbles each of which is blue, green or white. The probability of selecting a blue marble at random from the jar is $\frac{1}{3},$ and the probability of selecting a green marble at random is $\frac{4}{9}.$.How many white marbles does the jar contain? A)  12                  B)  6                    C)  9                                D)  11

Let there be b blue, g green and w white marbles in the jar. Then,$b+g+w=54$ ?.(i) $\therefore$   P (Selecting a blue marble) $=\frac{b}{54}$ It is given that the probability of selecting a blue marble is $\frac{1}{3}$. $\therefore$  $\frac{1}{3}=\frac{b}{54}\Rightarrow b=18$                     We have, P (Selecting a green marble) $=\frac{4}{9}$ (given) $\Rightarrow$            $\frac{9}{54}=\frac{4}{9}\Rightarrow g=24$ Substituting the values of b and g in (i), we get: $18+24+w=54\Rightarrow w=12$ Hence, the jar contains 12 white marbles.