There are 20 pieces of candy in a machine: 5 Hershey kisses, 6 Kit Kats, 4 Snickers,

Question:

There are 20 pieces of candy in a machine: 5 Hershey kisses, 6 Kit Kats, 4 Snickers, and 5 Paydays. The machine randomly selects one of the remaining candies when someone makes a purchase, and the candies are not replenished after the purchase (i.e., purchases are made without replacement). If X Kit Kats are contained in a purchase of Y candies, find E(X | Y = 4).