49. If two bulbs are randomly selected from the box of lightbulbs described in Exercise 40 (Section 2.3)

and at least one of them is found to be rated 75 W, what is the probability that both of them are 75-W bulbs? Given that at least one of the two selected is not rated 75 W, what is the probability that both selected bulbs have the same rating?

P1A 0 B2 P1A¿ 0 B2 P1B 0 A2 P1B¿ 0 A2 P1B 0 A2?

P1A 0 B2 P1A 0 C2 P1C 0 A2,