Suppose we have four boxes A, B, C and D containing coloured marbles as given below:

Box

Marble colour

Red

White

Black

A

1

6

3

B

6

2

2

C

8

1

1

D

0

6

4

One of the boxes has been selected at random and a single marble is drawn from it. If the marble is red, what is the probability that it was drawn from box A?, box B?, box C?

Question

Philoid · Accepted Answer

Let us assume R be the event of drawing the red marbles

Let us also assume E_A, E_B andE_C denote the boxes A, B and C respectively

It is given in the question that,

Total number of marbles = 40

Also, total number of red marbles = 15

∴

Probability of taking out the red marble from box A,

Also, probability of taking out the red marble from box B,

And, Probability of taking out the red marble from box C,