stete whether the two variables are a function and if so, identify independent and dependent variables. (see below)

Question

Please explain this one.  You walk through a used car lot and list the price and model year of each car you see. I feel like C makes sense.

 

A.  The situation cannot be described by a function.

B.  The situation can be described by a function. There is a dependent variable, but no independent variable. The dependent variable is the price.

C.  The situation can  be described by a function. The dependent variable is the price and the independent variable is the model.

 

D.  The situation can be described by a function. The dependent variable is the model and the independent variable is the price.

Answer 1

This is a fairly bad attempt to mathematize the used car world!

 

You could say that the price is a function of model & year (e.g. 2007 Chevvy, 2007 Ford, 2008 Chevvy, 2008 Ford, etc.) but the fact is (in the real world) that there are numerous parameters to model, such as Ford Focus, Ford Taurus, Ford Fusion, etc.) and other variations such as loaded v. basic, inline 6 cyl versus V8 or 4 cyl) and then there's the very important aspect of # of miles driven and general condition. It's a real fallacy to think that prices are nice functions, and it's also true that prices have a lot of wiggle room, which salesmen try not to yield. The only thing I can think of that has as much variability and unpredictability (and indeed, irrationality) is airline ticket pricing.

 

Your CommonCore-influenced curriculum probably wants you to choose C. But I prefer A. The question lacks, utterly, the precision that REAL MATHEMATICS thrives on.