Question

A box contains 4 red markers and 2 blue markers a marker is selected at random and it's color is noted. If it is red it is replaced; otherwise it is not. A second marker is selected and it's color is noted. If the second is blue, find the probability that the first was blue?

Answer 1

The probability of first one to be blue is
`(1)/(3)`.

Explanation:

In the given box, there are 4 red markers and 2 blue markers.

The given scenario will not affect the required probability as the selection of the second one is a case of future.

We need to find the probability of the first marker is blue.

The probability is
`(blue markers)/(total markers) = (2)/(6) = (1)/(3)`.