Question

A bag contains 3 red balls and 5 black balls. A ball is draw at random from the bag. What is the probability that the ball drawn is  not red? 

Answer 1

A bag contains 3 red and 5 black balls and a ball is drawn at random from the bag

TO FIND: Probability of getting a

(i) red ball

(ii) not red ball

Total number of balls `3+5=8`

 Probability of getting red ball `P (E)=3/8`

We know that sum of probability of occurrence of an event and probability of non occurrence of an event is 1.

`P(overlineE)+P(overlineE)=1`

`3/8+P(overlineE)=1`

`P(overlineE)=1-3/8`

`P(overlineE)=(8-3)/8=5/8`

Hence the probability of getting not red ball `P(overlineE)=5/8`