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  • Daniel Whittaker

    July 3, 2019 at 9:17 pm

    I’m thinking about my Linear Programming unit. A typical problem would be something like:

    “Sally makes gingersnaps and snickerdoodles to sell. She has 20 eggs and 15 cups of sugar. A dozen gingersnaps requires 3 eggs and 2 cups of sugar. A dozen snickerdoodles requires 2 eggs and 3 cups of sugar. She can sell 1 dozen cookies for $5 each. How can she maximize her sales?”

    Students really tend to struggle with the many steps in these problems. I always work hard to break down the steps and have them really understand, but they struggle. So, I’m trying to think through the process in this way.

    “Sally is making cookies to sell at the fair.” – What do you wonder? (What kind? How much do they cost? How much will she earn?)

    “How can she maximize her sales?” – (Advertise! Make more cookies!)

    “She makes snickerdoodles and gingersnaps and sells them for $5 per dozen.” – What do you notice/wonder? (What is keeping her from making as much as she wants? If she sells 100 dozen, that is $500!)

    “She has plenty of most ingredients, but only has 20 eggs and 15 cups of sugar.” – (I wonder how many eggs and how much sugar it takes to make those cookies.)

    “It takes 3 eggs and 2 cups of sugar for a dozen gingersnaps. It takes 2 eggs and 3 cups of sugar for a dozen snickerdoodles.”

    Now they have all the information, but will they be able to work out an answer? They could do it via some trial and error, but I’m not convinced this will get them to the correct answer.

    This is really thinking about next year. I always introduce the unit by having them create some lego furniture and working through the process that way, but they always get hung up on the constraints and the graphing part of the solution.

    • This reply was modified 2 years, 11 months ago by  Kyle Pearce.