Suppose that Neha is a diligent hard$-$working fourth$-$year college student. One Friday, she decides to start the day by working through $150$ practice problems to study for the informatics class. Using a table to track her progress throughout the day, she notices that as the hours pass, it takes her longer to solve the problems.

$\backslash$table$[[$Time$,$Total Problems Solved$],[7$:$00$ AM$,0],[8$:$00$ AM$,60],[9$:$00$ AM$,105],[10$:$00$ AM$,135],[11$:$00$ AM$,150]]$

Use the table to answer the following questions.

The marginal, or additional, gain from Bella's first hour spent working, from $7$:$00$ AM to $8$:$00$ AM$,$ is $$ problems.

The marginal gain from Bella's third hour spent working, from $9$:$00$ AM to $10$:$00$ AM$,$ is $$ prablems.

The following week, Bella's informatics faculty advisor gives her some advice. In all their years of teaching they claim to observe that working on $52\mathrm{.}5$ 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.

For each of the following activities, identify the flow of dollars as either household$-$to$-$firm or firm$-$to$-$household

Activity

Flow of Dollars

Kevin earns $$10$ per hour working at a library.

Maria pays a storekeeper $$2$ for a quart of yogurt.

Ana earns $$20,000$ from her $10\%$ ownership of Acme Industrial.

Simone spends $$50$ for a swimming lesson.

For each of the following activities, identify the flow of dollars as either household$-$to$-$firm or firm$-$to$-$household

Activity

Flow of Dollars

Kevin earns $$10$ per hour working at a library.

Maria pays a storekeeper $$2$ for a quart of yogurt.

Ana earns $$20,000$ from her $10\%$ ownership of Acme Industrial.

Simone spends $$50$ for a swimming lesson.