Kate’s preferences over Diet Coke (good 1) and generic diet cola (good 2) are perfect substitutes, but she prefers Diet Coke to generic diet cola. She is always willing to trade 2 Diet Coke’s for 1 generic diet cola. Suppose Kate has 15 dollars, and six-packs of Diet Coke sell for $3 and six packs of generic diet cola sell for $1. Graph Kate’s budget constraint and some representative indifference curves. What is her optimal bundle?