A bag contains 9 marbles: 2 are green, 3 are red, and 4 are blue. Ahmad 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.

Prob(red, then blue)

= (3/9)(4/8) = .....