A jar contains 36 disks: 9 each of four colors—red, green, blue, and yellow. Each set of disks of the same color is numbered from 1 to 9. Suppose you draw one disk at random from the jar. Define events R: get a red disk, and N: get a disk with the number 9.

a. Make a two-way table that describes the sample space in terms of events R and N.

b. Find P(R) and P(N).

c. Describe the event “R and N” in words. Then find the probability of this event.

d. Explain why P(R or N) ≠ P(R) + P(N) Then use the general addition rule to compute P(R or N).