You got to some party and decide to make a famous cake recipe. The recipe uses 6 pounds of chocolate and 2 pounds of flour in each batch. You will use this exact ratio for each cake to be perfect and you want to make as much cake as possible.

The utility curve is U(C,F)= min (C/6,F/2)

Chocolate costs $3/pound and Flour costs $7/pound. Your income is I and can be used to buy flour and chocolate. Also, you currently have 3 pounds of chocolate and you can't trade or sell this for anything.

Find the engel curve for Flour, F(I).