Question

A bag contains 24 marbles of which 12 are red, 8 are green and the remainder are multicolored. You select one marble at random from the bag with replacement.
a) What is the probability that the ball drawn is not a multi-coloured or not a red marble?
b) Given that a marble selected is not a red, what is the probability that it is a multicolored marble?

Answer 1

✔️a) 8/24 = 1/3

✔️b) 4/24 = 1/8

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Answer 2

Answer:

1) 1/3

2) 1/3

Step-by-step explanation:

We write the probabilities as follows :

Probability that the marble is red = 12/24 = 1/2

The probability that the marble is green = 8/24 = 1/3

The probability that the marble is multicolored = 4/24 = 1/6

1) The probability that the marble is not red or multicolored.

P(not red) = (4 + 8) / 24 = 1/2

P(not multicolored) = (12 +8) / 24 = 5/6

P(not red or multicolored) = 8/24 = 1/3

2) given that it is not red, the probability that it is multicolored.

= P(multicolored/red) = [P(not red) × P(multicolored] / P(not red)

We write this as follows :

[1/2 × 1/3] / 1/2

1/6 ÷ 1/2 = 1/3