A bag contains 5 black balls, 4 white balls and 3 red balls. If a ball is selected at random, the…

A bag contains 5 black balls, 4 white balls and 3 red balls. If a ball is selected at random, the probability that it is a black or a red ball, is
  1. $\frac{1}{3}$
  2. $\frac{1}{4}$
  3. $\frac{5}{12}$
  4. $\frac{2}{3}$

Solution

Required probability $ =\frac{5 C_1+3 C_1}{12 C_1}=\frac{5+3}{12}=\frac{8}{12}=\frac{2}{3} $

Asked in: AP EAMCET 2002

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