Please answer this question

1) Suppose you are delivering power to a load resistor using a non-ideal power supply with an emf E = 20 V and an internal resistance of r = 10 0. Under the maximum power transfer condition, calculate the efficiency of the power supply by taking ratio between the power delivered to the load and the total power output of the supply. (5 pt Bonus): Calculate the efficiency of the power supply when R = 100 0. Does this ratio invalidate the maximum power transfer theorem? Why or why not? Attach a separate page if necessary