Question

A box contains 5 red marbels, 8 white marbles and 4 green marbles, One marble is taken out of the box at ramdom. What is the probability that the marble taken out will be  not green?

Answer 1

 A box contains 5 red, 4 green and 8 white marbles and a marble is drawn at random.

TO FIND: Probability of getting a marble not green 

Total number of marble:  `5+4+8=17`

Total number of green marbles is 4 

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

Hence probability of getting green marbles `

p(overlineE)=4/17`

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`

`4/17+P(overlineE)=1`

        `  P(E)=1-4/17`

         ` P(E)=(17-4)/27=13/17`

Hence the probability of getting green marbles is `P(overlineE)=13/17`