Question

In a bucket there are 5 purple, 15 grey and 25  green balls. If the ball is picked up randomly, find the probability that it is neither grey nor purple?

(a) \(\frac{5}{9}\)

(b) \(\frac{12}{13}\)

(c) \(\frac{51}{43}\)

(d) \(\frac{2}{7}\)

I had been asked this question in quiz.

My question is based upon Geometric Probability topic in portion Discrete Probability of Discrete Mathematics

Answer 1

The correct answer is (a) \(\frac{5}{9}\)

To explain I would say: If the ball is neither grey nor purple then it must be blue. There are 45 balls in total of which 25 are green and so the probability of picking a purple ball is \(\frac{25}{45} = \frac{5}{9}\).