Suppose John views butter and margarine as perfect substitutes for each other:
(i) Draw a set of indifference curves that describe John's preference for butter and margarine.
(ii) Are these indifference curves convex? Why?
(iii) If butter costs 2,000/= per package and margarine only 1,000/= and if John has 20,000/= budget to spend for the month, which butter-margarine market basket will he choose? Show your answer graphically.