Halloween candy rankings. The website FiveThirtyEight. com published a story titled “The Ultimate Halloween Candy Power Ranking” (October 2017). The rankings were based on data collected from an online contest in which participants were asked which of two different Halloween candies they prefer. The two candies compared were randomly selected from 86 different candy varieties, ranging from Reese’s Peanut Butter Cups (ranked #1) to Good & Plenty (ranked #86).

a. How many different pair-wise comparisons are possible?

b. What is the probability that the two candies selected for comparison are Reese’s Peanut Butter Cups and Kit Kat (ranked #4)?

c. In addition to Peanut Butter Cups, three other Reese’s products were on the list: Reese’s Miniatures, Reese’s Pieces, and Reese’s Stuffed with Pieces. (All four were ranked in the top ten.) What is the probability that the two candies selected for comparison are both Reese’s products?