A viewer preference survey conducted by a cable-television network revealed that 46% of viewers watch sports, 31% watch comedy, and 33% watch drama. Of these viewers, 13% watch sports and comedy, 9% watch comedy and drama, and 11% watch sports and drama. Suppose 20% of viewers watch none of these 3 types of shows. What is the probability that a randomly selected person watches all three? I have no idea how to do this problem. I tried using a venn diagram, but that didn't seem to work.. And for this problem: In a card game, a hand of 5 cards contains at least 2 spades. What is the probability that there are exactly 4 spades in that hand? I tried doing 5C4(13/52)^4(39/52), but it wasn't correct..