Question

A bag contains 5 blue balls, 2 red balls and 3 green balls. If a ball is taken at random, what is the probability of getting not red ball from the bag?

Answer 1

Answer:

There is an 80% probability that the ball will not be red.

Step-by-step explanation:

Answer 2

Answer:

4/5

Step-by-step explanation:

Given the bag contains 2 red balls , 5 blue balls and 3 green balls.

Probability of getting a red ball is 2/10 = 1/5

 But we need probability of not getting a red ball

Probability of not getting a red ball = 1 - probability of getting a red ball.

i.e., 1 - 1/5

= 4/5

Hence the probability of not getting a red ball is 4/5.

II Method:

The answer above tells us that the probability of picking either a blue or a green ball is 4/5

P(a blue ball) = 3/10

P(a green ball) = 5/10

Picking a blue ball and picking a green ball are mutually exclusive that is, they contain no item in common, in which case

P(a blue ball or a green ball) = P(a blue ball) + P(a green ball) (Addition Rule)

= 3/10 + 5/10

= 8/10

= 4/5

Therefore,

P(not a ball red in colour) == P(a ball blue in colour) + P(a ball green in colour) = 4/5