The point of the question is that there is no mathematically "right" answer. The interviewer knows the answer from experience, and (s)he's testing two things: whether the interviewee's intuition on the market is right, and, if not, how well the interviewee takes to being corrected.
Your answers are "right", in that they are possible, but they are not the numbers the interview wants to hear.
That makes more sense. I thought there was some obvious game theory principle I was missing, since somebody commented that they could answer the question without knowing anything about trading.
Your answers are "right", in that they are possible, but they are not the numbers the interview wants to hear.