Using the following information, calculate total utility and marginal utility.
a. Plot the total utility curve.
b. Plot marginal utility directly below total utility.
c. At what marginal utility value does total utility reach a maximum?
Number of units for the first unit: 300
Number of units for the second unit: 250
Number of units for the third unit: 220
Number of units for the fourth unit: 160
Number of units for the fifth unit: 100
Number of units for the sixth unit: 50
Number of units for the seventh unit: 20
Number of units for the eighth unit: 0
Number of units for the ninth unit: -250