English is a syntactical construct created by human beings and has absolutely no bearing on how mathematics work. They're 100% irrelevant. Japanese people read from top-to-bottom, so does that mean you have to solve the numerators of fractions before solving the denominator? Arabic is read right-to-left, does that mean that in English speaking countries the answer is 288 yet in Arabic speaking countries the answer is 2?
I am truly sorry that you were taught something that isn't true. The fact of the matter, though, is that you straight up are not qualified to make the decision on how math problems should be solved. In fact, nobody is. That's the glorious thing about math: it itself is inherently unambiguous. The issue is with our representation of the question without parenthesis or using a fraction bar. Nobody has decided that / can only pertain to the terms immediately to the left and right of it.
Let me say this one more time, loud and clear:
You are not qualified to challenge a math professors view. Your opinion on the answer does not matter.