There are three goods you are interested in purchasing, X, Y and Z. You notice that the price of Z has fallen. Assume that the cross price elasticity between Z and Y is -1.5, the cross price elasticity between Y and X is 3.0, and the cross price elasticity between Z and X is 0.50. It would make sense that:
OX and Z are unrelated; Y is complementary to X.
OY and X are substitutes; Y is complementary to Z.
OX and Z are complements; Y and Z are substitutes.
OZ and X are complements; Y and X are substitutes.
