Question

A jar contains 11red marbles, 12 blue marbles and 6 white marbles. Four marbles from the jar are selected. With each marble being replaced after each selection. What is the probability that the first red marble chosen is on the 5th selection?

Answer 1

Red on the 5th draw = 0.0907

Explanation:

The first to fourth selections are all the same.

Blue + white = 12 + 6 = 18

The total number of marbles is 11 + 12 + 6 = 29

P(~ red) for the first four times = (18/29)^4 = 0,1484

Now on the 5th time, the first red is 11/18

So the Probability is 0.1484 * 11/18 = 0.0907