You are packing for a road trip and you buy snack packages (same size, same weight) for the trip. You buy 6 potato chips, 5 doritos, and 3 corn curls. You put them in a bag and mix them up. During the trip, you reach into the bag and pull out two packages at random, one at a time. Draw a tree and calculate the probability of each outcome. Use P for potato chips, D for doritos, and C for corn curls. What is the probability of picking two snacks of the same type?