Henry Hanover is currently consuming 20 cheeseburgers and 20 Cherry Cokes a week. A typical indifference curve

Question:

Henry Hanover is currently consuming 20 cheeseburgers and 20 Cherry Cokes a week. A typical indifference curve for Henry is depicted below.

(a) If someone offered to trade Henry one extra cheeseburger for every Coke he gave up, would Henry want to do this? No.
(b) What if it were the other way around: for every cheeseburger Henry gave up, he would get an extra Coke. Would he accept this offer? Yes.
(c) At what rate of exchange would Henry be willing to stay put at his current consumption level? 2 cheeseburgers for 1. Coke.