Brian is taking three courses this semester: economics, statistics, and finance. He has decided to spend 19 hours per week studying in addition to attending all his classes and his objective is to maximize his average grade, which means maximizing the total of his grades in the three courses. The table shows Brian’s estimate of the relation between time spend studying and his grade for each course. It is assumed that Brian will spend at least 4 hours per week studying each of the three courses.