Question

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

Answer 1

Total number of possible outcomes, n(S) = 5 + 8 + 4 = 17 

(i) Number of favorable outcomes, 

n(E) = 5

∴ P(E) = \(\frac{n(E)}{n(S)}\) = \(\frac{5}{17}\)

(ii) Number of favorable outcomes, 

n(E) = 8

∴ P(E) = \(\frac{n(E)}{n(S)}\) = \(\frac{8}{17}\)

(iii) Number of events of drawing a green marble = 4

 ∴ P(E) = \(\frac{n(E)}{n(S)}\) = \(\frac{4}{17}\)

Probability of not drawing green marble = 1 – P(E)

= 1 - \(\frac{4}{17}\) = \(\frac{13}{17}\)