A bag contains 5 white and 7 red balls. One ball is drawn at random. What is the probability that ball drawn is white?

Total no. of possible outcomes = 12 {5 white, 7 red}

E ⟶ event of drawing white ball.

No. of favorable outcomes = 5 {white balls are 5}

Probability, P(E) = (No. of favorable outcomes)/(Total no. of possible outcomes)

P(E) = 5/12

Total numbers of red balls = 7

Number of white balls = 5

Total number of Non red balls = 7 + 5 = 12

Probability of getting a non-white ball is = Total number of non-white balls/Total number of balls

= 5/12

∴ Probability of getting a non-white ball is 5/12

Total numbers of red balls = 7 

Number of white balls = 5 

Total number of Non red balls = 7 + 5 = 12 

Probability of getting a non black ball is = \(\frac{Total\,number\,of\,white\,balls}{Total\,number\,of\,balls}\) = \(\frac{5}{12}\)

Sample space, n(S) = 12 

Number of events of getting white ball, 

n(E) = 5

∴ P(E) = \(\frac{n(E)}{n(S)}\) = \(\frac{5}{12}\)