A box contains 5 red marbles, 8 white marbles and 4 green marbles. One marble is taken out of the box at random. What is the probability that the marble taken out will be

(i) red?

(ii) white?

(iii) not green?

No. of possible outcomes = 17 (5 red + 8 white + 4 green)

(i) No. of favourable outcomes (for drawing a red marble) = 5

P(drawing a red marble)

= $\dfrac{\text{No. of favourable outcomes}}{\text{No. of possible outcomes}} = \dfrac{5}{17}$.

Hence, probability of drawing a red marble = $\dfrac{5}{17}$.

(ii) No. of favourable outcomes (for drawing a white marble) = 8

P(drawing a white marble)

= $\dfrac{\text{No. of favourable outcomes}}{\text{No. of possible outcomes}} = \dfrac{8}{17}$.

Hence, probability of drawing a white marble = $\dfrac{8}{17}$.

(iii) Since, there are only 3 coloured marbles in the bag.

∴ P(not drawing a green marble) = P(drawing a red or white marble)

No. of favourable outcomes (for drawing red or white marbles) = 13 (5 red + 8 white)

P(not drawing a green marble)

= $\dfrac{\text{No. of favourable outcomes}}{\text{No. of possible outcomes}} = \dfrac{13}{17}$.

Hence, probability of not drawing a green marble = $\dfrac{13}{17}$.