One of my goals this year was to use 3 act math tasks in class this year. My first one was “How much does a 100x100 In-n-Out cheeseburger cost?” by Robert Kapinsky. Several weeks ago, I also tried the “Fall of Javert” by Mathalicious. Now, I want to tell you about my experience using “How did someone get a $103,000 speeding ticket?” by Robert Kapinsky.

We were in the middle of our unit on the introduction to functions. I knew that I wanted to review function notation during the lesson.

As bellwork, I had my students graph the equation of several lines. It was easy peasy for them, but I like to throw in easy stuff sometimes to keep their skills sharp. I had put this lesson title on my student’s calendar, so there was lots of buzz about what we were going to do in class.

First, I skimmed/read the Wall Street Journal article to my students. They interrupted me a lot to ask questions and interject their thoughts. They were not impressed with the idea of graduated fines; it made for an interesting discussion.

When we got to the question, my students immediately knew what information they needed. I gave my students the formula to calculate the fine. I didn’t show them the code that the police use to calculate the ticket though. If I did this again, I probably would. Also, I didn’t mention rounding. I wanted to see if they could figure that part out on their own. I also wrote everything in function notation as I talked through the formula.

I had my students answer the following questions:

- What was Anssi Vanjoki’s monthly income?
- What was Anssi Vanjoki’s annual income?
- How much would the traffic ticket be if you received the same speeding ticket and made 60,000 per year?
- How much would the traffic ticket be if you received the same speeding ticket and made 45,000 per year?
- Convert all of your answers above to US dollars.
- Graph the equation you used for Anssi Vanjoki’s income and describe the graph.

These questions were easy for my students. I knew they would be (because it was basically review), but I still really wanted to do this with my students. My kids are 15-16 and are just learning to drive. I knew this lesson would get them excited and really hit home with them.

As they worked on the questions above, we kind of just talked as a class. A few of the students tried to think up what the “most severe” violation could be. They decided that a drunk driver crashing into a semi truck hauling babies and killing them all would be the most severe. Crazy kids. Also, my husband used to be a police officer, so I told them a couple of stories that he had about drunk drivers. Even though it wasn’t math related, I had their undivided attention, so I figured I’d use it as a life lesson.

The hardest part for my students was keeping the monthly and yearly income straight. I’m not really sure why though. I really enjoyed doing this lesson with my students.