# SMU MBA ASSIGNMENTS

## A bag contains 5 white, 6 red, 2 green and 2 black balls. One ball is selected at random from the bag. Find the probability that the selected ball is-

December 02, 2017 By: Meliza Category: 1st SEM

1. A bag contains 5 white, 6 red, 2 green and 2 black balls. One ball is selected at random from the bag. Find the probability that the selected ball is-
2. white
3. non-white

iii.        white or green

1. black or red

Solution

The bag has a total of 15 balls. Since the ball drawn can be any one of them, there are 15 equally likely, mutually exclusive and exhaustive outcomes. Let events A, B and C ,D be

A: selected ball is white

B: selected ball is non-white

C: selected ball is white or green

D: selected ball is black or red

(i)  There are 5 white balls in the bag. Therefore, out of the 15 outcomes, 5 are favourable to event A.

∴P [white ball] = P (A) = 5/15 = 1/3

(ii)  Event B is the complement of event A. Therefore,

∴ P[non-white ball] = P(B) = 1 – P(A) = 1 – 1/3 = 2/3

(iii)   There are 5 white balls and 2 green balls in the bag. Therefore, out of 15 outcomes, 7 are either white or green.

∴ P[white ball or green ball] = P(C) = 7/15

(iv) )   There are 2 red balls and 2 black balls in the bag. Therefore, out of 15 outcomes, 4 are either white or green.

∴ P[white ball or green ball] = P(C) = 4/15