Technically true but if real numbers are allowed you don't have a puzzle. Rather, you have a silly puzzle that consists in checking if the interviewee will say, "Waaaiiiit a second, is any number allowed? Because then you can never win!" and the interviewer saying, "Nicely done!". Nevertheless, the assumption should be stated.

The random selection omission is intentional.

And that's all hinged in the expectations of the intent of the question, if it is attention to details, the real number scenario is completely reasonable. If it is not, you can pick apart these types of puzzles and seem overly hard to work with.