A bag contains 2 red marbles and 4 blue marbles.

Question

What is the probability that you select 2 red marbles if you reach in the bag randomly grab a marble, DO NOT REPLACE IT, and then reach in and randomly grab a second marble?

Answer 1

The prob of the first being red is 2/6.  Once one is removed the odds of the second are 1/5.  Multiply them together to get the total probability:

 

2/6 x 1/5 = 2/30 = 1/15