Systems of inequalities: Really?

I wrote a while ago on the topic of word problems,

I will consider my career a success when my students no longer tell me that they are bad at (or good at) word problems.

And then I had the opportunity to meet Dan Meyer recently. He has written extensively on pseudocontexts, his word for the word problems I was railing against.

In that spirit, I need to get the following example off my chest, from a College Algebra text I no longer use.

We are supposed to set up a system of inequalities (“at most an additional 10 gallons of gas”) and solve with techniques of linear optimization.

But how could the answer be anything but, “Put as much as possible into the moped; put the rest into the car”?

And wouldn’t the problem be more interesting if Omar spent a few bucks on a gas can? Then some of his previous money goes to something other than gas, but buys more miles because he can put it in the moped.

And why must he spend all of his gas money at once?

And if he does have to do so, how is he getting both car and moped to the gas station at the same time?

And does that little yellow car really only get 20 mpg?


One response to “Systems of inequalities: Really?

  1. Ow, you made me slap my hand against my head really hard. This question is bad enough, but then the expected technique just makes it worse.

    Shouldn’t he just sell the car and use its sale for gas money for the moped? He could probably get like 10,000 miles that way.

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