Assume the demand function for basketballs is given by QD = 150 - 3P + 0.1I, where P = price of a basketball and I = average income of consumers. Also, assume the supply of basketballs is given by QS =2P. If the market for basketballs is perfectly competitive and the average income is equal to $1,500, what are the equilibrium price and quantity? What if a 20% income tax is introduced?