Assume the market demand for tuna cans may be written as Q' = 45 - 2 x p C + psic + 0.3Y (where p - price of tuna cans and psic price of sardine cans, and y - income). Further assume that both tuna cans and sardine cans sell for $1 and income is $20. Calculate cross-price elasticity for tuna cans and identify whether the goods are substitutes or complements. Please make sure to show all your steps