Harrison plans to spend a total of six hours to study for his exams in Economics and Geography. The following table shows his expected mark on each exam based on the number of hours spent studying each course. For example, if he spends all six hours studying Geography, he expects to get 84 marks in his Geography exam.

Hours Spent Studying Geography

Mark in Geography

Hours Spent Studying Economics

Mark in

Economics

0

0

0

0

1

25

1

20

2

45

2

35

3

60

3

47

4

70

4

57

5

78

5

63

6

84

6

66

a) What are the seven specific production combinations that lie on Harrison's production possibilities frontier (PPF)?

b) What is Harrison's opportunity cost of getting 63 marks in Economics?

c) Is Harrison's PPF concave to the origin (i.e. becoming steeper when you move rightward along the curve)? Prove your answer WITHOUT drawing Harrison's PPF. (Hint: what is the relationship between slope and opportunity cost?)

d) What are two specific and distinct ways for Harrison to increase his expected mark in both exams at the same time?