I asked my college sophomore son this question. He looked at it for a couple of seconds and answered correctly, 7. I asked why, and he said, "Order of operations."

I then asked my high school freshman daughter and she gave me the same answer. When I assked why, she said, "Please excuse my dear Aunt Sara." This is a phrase to remember order of operations (Parentheses, Exponents, Multiplication/Division, and Addition/Subtraction.

The order of operations is not arbitrary or optional, and therefore 7 is the only correct solution to the problem.