Must Problem, Quiz Explanation

Hi! Just wondering if perhaps this quiz question has a bug? It says the correct answer includes “The Sales Tax was more than $1.40.” I recognize that this answer DOES cause a problem when we are going by our must problem solving technique, but technically it shouldn’t be true since what MUST be true is that the sales tax is LESS than $1.40. I don’t know if that makes sense, but I wanted to make sure I wasn’t missing something. Thanks for the help. This course has been a life saver.


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Hi @noragleed, thanks for posting!

Yes, it does look like this variant of the question needs to be updated.

Basically, the strategy we teach for “must problems” is a good shortcut that will work on GRE questions, but it isn’t mathematically sound and it won’t work with every possible value in the real world.

We generate semi-random values in the questions to allow you to drill them repeatedly, and in this case it looks like we need to update the logic to ensure the values are within the ranges you’d see on the actual GRE.

We’ll look into it - thanks for letting us know!

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