Your question is Scaling a Food Delivery System. 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).
Design a food delivery system and explain how you would scale it to millions of customers.
Address the marketplace strategy, customer and merchant acquisition, delivery economics, operational capacity, geographic expansion, and the metrics you would use to manage growth. Make your assumptions explicit, prioritize trade-offs, and explain how the model changes as volume increases.