The demand for beer in Japan is given by the following equation: Q^d = 700 2P P_N + 0.1I, where P is the price of beer, P_N is the price of nuts, and I is average consumer income.

a) What happens to the demand for beer when the price of nuts goes up? Are beer and nuts substitutes or complements? - prove (2 marks)

b) What happens to the demand for beer when average consumer's income rises? (1 marks)

c) Graph the demand curve for beer when P_N = 100 and I = 10,000. (2 marks)