Your question is System Design with Sensors. 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).
You have a conveyor belt moving boxes from point A to B with four sensors along the way; how do you design a system to ensure high-quality operation while limiting the belt to 10 boxes at a time?