An urn contains 9 red, 7 white, and 4 black balls. A ball is drawn at random. Find the probability that the ball is drawn is

red or white

We know that,

Probability of occurrence of an event

By permutation and combination, total no.of ways to pick r objects from given n objects is ⁿC_r

Now, total no.of ways to pick a ball from 20 balls is ²⁰c₁ = 20

Our desired output is to pick a white or red ball. So, no.of ways to pick a white or red ball from 16 balls(because there are a total of 16 balls which are either red or white) is ¹⁶c₁ = 16

Therefore, the probability of picking a white or red ball

Conclusion: Probability of picking a white or red ball from 9 red, 7 white, and 4 black balls is