There are 9 marbles in total in the bag. Since there are 3 red marbles the probability of drawing out a red marble is 3/9 which can be simplified to 1/3
blue marble =1
green marble= 2
yellow marble = 3
red marble = 3
probability of picking a red marble without looking = 3/1+2+3+3
P(red marble)=3/9
P(red marble) =1/3
