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Nobody likes getting tickets. For many people they’re merely an annoyance, but for people struggling to make ends meet, they can be a serious burden. And since many states levy additional monthly fees when people can’t pay off fines in their entirety, some people get stuck in a cycle of debt that’s extremely difficult to escape.

In this lesson students use linear equations and solve linear systems to examine what happens when people are unable to pay small municipal fines. They also discuss what can happen to the most financially vulnerable citizens when cities rely heavily on fines for revenue.

Students will

  • Given gross monthly income and list of applicable taxes and expenses, calculate net monthly income
  • Given a monthly rate of savings, calculate how long it will take someone to pay off a fine
  • For a given fine, monthly savings rate, and monthly fee, solve a system of linear equations in order to determine how long it will take to pay the total, along with the value of that total
  • Discuss the impact of cities’ relying heavily on fines for support, particularly for the most vulnerable citizens

Before you begin

Given a value and a constant rate of change, students should be able to construct tables of values, plot points, and graph the resulting linear relationship.

Common Core Standards

Content Standards
Mathematical Practices


John Oliver, Hali Woods, Tom Barrett, Harriet Cleveland, image courtesy of Chris Yarzab (