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 red marble = 
= 
(ii) Number of white marbles = 8
Probability of white marble= 
= 
(iii) Number of green marbles = 4
Probability of green marbles
= 
= 
Probability of not getting a green marble = 1 - 
= 
20