probability question

Question

you have a bag of 17 marbles. four are blue, 6 are green, 2 are red, and 5 are yellow. what is the probability of drawing a red marble, keeping it, then drawing a blue marble?

Answer 1

Pr(R then B) = 2/17 x 4/16 = 1/34 - about 3^ chance of getting red then blue

2 ways out of 17 to get a red first

4 ways out of 16 to get blue next

multiply those probabilities to get 2/17 x 4/16 = 2/17 x 1/4 = 1/34