Welcome to your interview.
The question is on your right: Market Sizing and Profit Estimation. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
How many chicken rice portions could you sell at a stall at XXX University, and what profit could you make from that stall?