Ch-ch-ch-changes! Mathalicious is now Citizen Math . Please visit www.CitizenMath.com for the real-world math lessons you know and love. Alternatively, you can continue to access Mathalicious.com until the end of the school year, at which point Mathalicious will ride off into the sunset. For more details about the transition to Citizen Math, please click here.
Thumbnail new
How do municipal fines affect people with different incomes? Cities and towns around the country rely on parking and speeding tickets to generate much-needed revenue. Unfortunately these fines can trap the neediest residents in a cycle of debt, especially when they’re compounded by monthly late fees.

In this lesson, students write, solve, and graph systems of linear equations to determine how long it takes to pay off a ticket and debate the fairest ways for cities to raise revenues without harming their poorest residents.

Students will

  • Write and solve a system of linear equations and interpret the intersection in a real-world context
  • Explore how changing the slopes and y-intercepts affects where (and if) two lines intersect
  • Use a unit rate to create a table, graph, and equation

Before you begin

Students should be comfortable relating a scenario to an equation to a graph. Previous experience with systems of equations is not needed.

Common Core Standards

Content Standards
Mathematical Practices


John Oliver, Hali Woods, Tom Barrett, Harriet Cleveland. Image courtesy of Chris Yarzab (https://www.flickr.com/