Question

A bag contains marbles: 10 2 are green, 3 are red, and 5 are blue. Debra chooses a marble at random, and without putting it back, chooses another one at random. What is the probability that the first marble is red and the second is blue? Write your answer as a fraction in simplest form.

Answer 1

3/9•5/9=15/81=5/27
Because the first time you can take 3 from 10 marbles, and the second time there are 5 marbles from the 9 marbles left.