Question

You have 9 hours to study for two final exams, Economics and Biology. Your enjoyment of studying each subject is the same. If your goal is to maximize the sum of the two final exam grades, determine how many hours to spend studying for each.

Economics

Hours	Grade	AP	MP
0	25
1	46	46	21
2	60	30	14
3	73	24.3	13
4	84	21	11
5	93	18.6	9
6	99	16.5	6
7	100	14.3	1

Biology

Hours	Grade	AP	MP
0	60
1	70	70	10
2	78	39	8
3	84	28	6
4	89	22.3	5
5	93	18.6	4
6	95	15.8	2
7	96	13.7	1

Answer 1

According to law of equimarginal utility, consumer is at equilibrium when marginal product for the last hour from both goods are same.

and total number of hours spent on both good should be 9.

thus you should study Economics for 6 hours and Biology for 3 hours