Your question is Logic Puzzle Under Pressure. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Solve this brain teaser or logic puzzle under time pressure while explaining your underlying thought process. State your assumptions, organize the problem into manageable parts, and communicate how you evaluate possible solutions. The interviewer is assessing your reasoning process, composure, prioritization, and ability to explain uncertainty, not just whether you reach the correct answer.