A marble is picked out at random from a box containing 5 red marbles, 8 white marbles and 4 green marbles. What is the probability that the marble picked out will be
A marble is picked out at random from a box containing 5 red marbles, 8 white marbles and 4 green marbles. What is the probability that the marble picked out will be

(i) a red marble?

(ii) a white marble?

(iii) is not a green marble?

Solution:

The Total number of marbles in the box = 5+8+4 = 17

P(E) = (Number of favourable outcomes/ Total number of outcomes)

(i) Total number of red marbles in the box = 5

P (red marble) = 5/17 = 0.29

(ii) Total number of white marbles in the box = 8

P (white marble) = 8/17 = 0.47

(iii) Total number of green marbles in the box = 4

P (green marble) = 4/17 = 0.23

∴ P (not a green marble) = 1-P(green marble) = 1-(4/7) = 0.77