Question

A bag contains 8 red marbles 3 blue marbles and 1 green marble find P not blue

Answer 1

Sample space={8 R, 3B, 1 G} = 12 OUTCOMES

P( 1 blue) =3/12 = 1/4
P(NOT blue) = 1 - P(blue) = 1 - 1/4 = 3/4

Answer 2

`P(\text{Not blue})=(3)/(4)`

Explanation:

We have been given that a bag contains 8 red marbles 3 blue marbles and 1 green marble. We are asked to find the probability of not getting a blue marble.

Probability of not getting a blue marble will be equal to probability of getting red marble plus probability of getting green marble.

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

`P(Red)=(8)/(12)`

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

`P(Green)=(1)/(12)`

`P(\text{Not blue})=P(\text{Red})+P(\text{Green})`

`P(\text{Not blue})=(8)/(12)+(1)/(12)`

`P(\text{Not blue})=(8+1)/(12)`

`P(\text{Not blue})=(9)/(12)`

`P(\text{Not blue})=(3*3)/(3*4)`

`P(\text{Not blue})=(3)/(4)`

Therefore, the probability of not getting a blue marble is
`(3)/(4)`.