Question

A bag contains 5 white balls, 7 red balls, 4 black balls and 2 blue balls. A ball is drawn at random from the bag. Find the probability that the drawn ball is (i) white or blue, (ii) neither white nor black.

Answer 1

Given: A bag with 5 white, 7 red, 4 black and 2 blue balls; one ball is drawn at random.

Step-wise calculation:

1. Total number of balls = 5 + 7 + 4 + 2

= 18

2. (i) White or blue:

Favourable = 5 + 2

= 7 

⇒ P(white or blue) = `7/18`.

3. (ii) Neither white nor black:

Favourable = Red + Blue

= 7 + 2

= 9 

⇒ P(neither white nor black) = `9/18 = 1/2`.