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?
Total number of marbles = 5 + 8 + 4
= 17
(i)Number of red marbles = 5
Probability of getting a red marble $=\frac{\text { Number of favourable outcomes }}{\text { Number of total possible outcomes }}$
$=\frac{5}{17}$
(ii)Number of white marbles = 8
Probability of getting a white marble $=\frac{\text { Number of favourable outcomes }}{\text { Number of total possible outcomes }}$
$=\frac{8}{17}$
(iii)Number of green marbles = 4
Probability of getting a green marble $=\frac{\text { Number of favourable outcomes }}{\text { Number of total possible outcomes }}$
$=\frac{4}{17}$
Probability of not getting a green marble $=1-\frac{4}{17}=\frac{13}{17}$