Question

A bag contains 4 red, 6 blue, 4 yellow and 2 green marbles. Once a marble is selected, it is not replaced. What is the probability that in 3 successive draws you will get exactly one blue, one red and no green

Answer 1

0.0857

Explanation:

What we need is, B R -G, successively. We do not add each probability, but multiply them.

P(1st marble is B) = 6 / 16

P(2nd marble is R) = 4 / 15

*your sample space decreases because you took one marble already before, the Blue one

P(3rd marble is not Green) = 12/14

** it's 12 because you took 2 non-Green marbles before

*** it's 14 because you took 2 marbles before

To arrive at the final answer, just multiply all probability.