The indifference curve
16. In Europe tennis balls are sold in packages of four, but in North America they are sold in packages of three. Let X1 be the number of European packages of tennis balls, and let X2 be the number of American or Canadian packages of tennis balls. Draw the indifference curve through the bundle (6,8) of someone who uses a lot of tennis balls. Assume that the individual cares only about the total number of tennis balls, and doesn’t care about how they are packaged.