Suppose there is an urn containing 20 green balls and 30 red balls. A single trial consists of drawing a ball randomly from the urn and then putting it back in the urn. The experiment consists of 4 independent trials.

a)List each outcome (sequence of 4 trials) in the sample space together with its probability. What do you notice about the probabilities of outcomes that have the same number of green balls?

b)Let Y be the number of green balls drawn. List the outcomes that make up each of the following events:

Y=1, Y=2, Y=3 and Y=4