5. A decision at the margin

Suppose that Alivia is a diligent second-year college student. One Saturday, she decides to start the day by working through 250 sample multiple choice problems to study for her econometrics class. She starts work at 7:00 AM and uses a table to keep track of her progress throughout the day. She notices that as she the hours pass, it takes her more time to solve the problems.

Time	Total Problems Solved
7:00 AM	0
8:00 AM	100
9:00 AM	175
10:00 AM	225
11:00 AM	250

Use the table to answer the following questions.

The marginal, or additional, gain from Alivia's second hour spent working, from 8:00 AM to 9:00 AM, is

problems.

The marginal gain from Alivia's fourth hour spent working, from 10:00 AM to 11:00 AM, is

problems.

The following week, Alivia's econometrics faculty advisor gives her some advice. In all their years of teaching they claim to observe that working on 87.5 multiple choice questions boosts a student's test score by about the same amount as spending an hour reviewing lecture notes. For simplicity, assume students are able to review lecture notes at a constant pace during each hour spent studying.

Given this information, in order to use her 4 hours of time spent studying to get the highest possible test score, how many hours should she have spent solving multiple choice problems, and how many hours should she have spent reviewing lecture notes?

1 hour working on problems, 3 hours reading

2 hours working on problems, 2 hours reading

3 hours working on problems, 1 hour reading

4 hours working on problems, 0 hours reading