Hello, in this question from Test 12 Section 4, they never specify that n ≠ 0. I know this is a unique case, but shouldn’t we consider it regardless? I would not want to ÷ both sides by n because they never state that n ≠ 0, and in the case that we are choosing numbers and we select n = 0, QA = QB. Then, in other cases, QA > QB, so shouldn’t the answer be need more information? The cost of 0 cans should be 0, correct? Thank you!
There’s an ETS principle called reasonable assumptions which means that you can assume things that would be obvious. Such as the number of days in a week. And in this case, that n > 0. I’m not sure whether ETS would add n > 0 in such a question today, though.