X in terms of Y

[MatthewM36]

A student in class mentioned a strategy to deal with all of the "x in terms of y" problem solving questions...similar to the what must be true and what would be true problem questions. Any idea what strategy that is? I find back solving helpful for these questions, but want to confirm.

[Sage Pearce-Higgins]

Definitely ask your instructor more about this one; I guess the student was referring to a strategy we call 'Smart Numbers with Variables in the Answer Choices' or ViC for short. In short, when you have a problem with variables in the answer choices you're free to assign values for those variables. Then you can work out the answer to the question, not as an algebraic expression, but as a real number. Finally, you plug in the smart number(s) you chose into the answer choices to see which one gives the correct value. Check out PS186 from OG2020 for an example of that kind of problem and try assigning a value for "d" to see what happens.

This is a good strategy for avoiding algebra on a problem but it comes with a bit of a warning - on some problems it can be pretty complicated. You'll find some more about this in chapters 13 and 23 of All the Quant.