Real Life Math, Any ideas???

Comment by Tammy Moore on July 13, 2009 at 5:45pm

One of the kids' favorites was a real life puzzle in which they were to compare the family's cost given the two options ...

Total cost if mom drives daughter to social events, drop her off, and make a second trip when the event was over

compared to

teen being put on insurance so that she could drive herself to the events.

We were having a unit on the usefulness of graphing linear equations when we did this unit. The kids created a cost vs trips graph and plotted a line that showed the equation with the insurance fee built in to that month. They learned enough to know that the line would cross the y-axis at the cost of the insurance fee and that the slope would be the cost of the car's operation for one trip to and back for each event. For the second line, the line crossed the y-axis at 0 since there would be no monthly insurance fee. The slope of the line was greater though because two round trips would have to be made per event. The kids realized that a graph like this could show them some valuable information such as 'Up to how many events is it cheaper to have mom drive?', 'At what point are both the same cost?', and "At how many event trips will it make more sense to go ahead and put the teen on the family's insurance?'. Since so many of the kids were at that age where their family was grappling with that very decision, there was high motivation. In the process, we had a chance to talk about the cost of adding teens to insurance and why it was so high, figuring cost per trip based on current gas prices and the gas mileage they computed with their own family's cars. It had a lot of practical use and the kids learned to apply linear equations and graphing as a problem solving tool.

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