Please consider Ethan. At his current consumption bundle, the value of Y in terms of X to him is 2 X.

a.What Ethan's MRSXYand MRSYXat the current consumption bundle?

MRSXY:

MRSYX:

b.Please consider the indifference curve that passes through the current consumption bundle, which satisfies the all properties of the indifference curves. Then, Ethan moved down along the indifference curve. Because of the movement, MRSXYchanged to one of them, which?

-1/2,-1,-1/3,-2

Please consider Yan. His MRSXYis -5 at his current consumption bundle and that the price of X is PX= 20 and the price of Y is PY= 4. Does this necessarily mean that Yan's current consumption bundle is the optimal one? If so, answer yes. If not, why?