A demand function is given by Qd = -30P + 0.05Y + 2P +4T , where Q is quantity demanded, P is the price of the good, Pr is the price of a related good, and T is taste. Is Pr a complement or a substitute? Graph this function assuming Y + 5000, P = 25, and T = 30 . What happens to the graph if T = 50? When tastes and preferences change ceteris paribus, what happens to demand?