# A Bag Contains 5 Black Balls, 4 White Balls and 3 Red Balls. If a Ball is Selected Randomwise, the Probability that It is Black Or Red Ball is (A) 1/3 (B) 1/4 (C) 5/12 (D) 2/3 - Mathematics

MCQ

A bag contains 5 black balls, 4 white balls and 3 red balls. If a ball is selected randomwise, the probability that it is black or red ball is

•  1/3

• 1/4

•  5/12

•  2/3

#### Solution

2/3

Out of 12 balls, one ball can be drawn in 12C1 ways.
∴  Total number of elementary events = 12C1 = 12
Out of fivne black balls, one black ball can be chosen in 5C1 = 5 ways.
Out of three red balls, one red ball can be chosen in 3C1 = 3 ways.
∴ Favourable number of events = 5 + 3 = 8
Hence, required probability = $\frac{8}{12} = \frac{2}{3}$

Concept: Probability - Probability of 'Not', 'And' and 'Or' Events
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#### APPEARS IN

RD Sharma Class 11 Mathematics Textbook
Chapter 33 Probability
Q 25 | Page 72