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1. Given the following demand function Qa = 9 - 3Pa - 3Pb + 0.4Y and given Pa = 1, Pb = 4, Y = 20 find (i) the direct price (Pa ) elasticity (ii) the cross price (Pb ) elasticity (iii) the income (Y) elasticity and comment on the economic significance of their values. 2. The marginal cost function (MC) for a firm is given by MC = 22 + 20q where q is the output of the firm. The marginal revenue function (MR) is given by MR = 88 -2q. (a) Does the firm operate in a perfectly competitive market? (b) Determine the level of output at which profits are maximised