Question

A bag contains 5 white and 7 red balls. One ball is drawn at random. What is the probability that ball drawn is not black? 

Answer 1

GIVEN: A bag contains 6 red, 8 black and 4 white balls and a ball is drawn at random

TO FIND: Probability that the ball drawn is not black

Total number of balls `6+8+4=18`

Total number of black balls is 8

We know that PROBABILITY =` "Number of favourable event" /"Total number of event "`

Probability of getting a black ball P(E) `8/18=4/9`..........(1)

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

Hence

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

`4/9+P(overlineE)=1`

`P(overlineE)=1-4/9` 

`P(overlineE)=5/9`