It's a good interview question. Here's how I would answer it: At scale there would be drivers dedicated to filling up at only one restaurant, and then deliveri

It's a good interview question. Here's how I would answer it: At scale there would be drivers dedicated to filling up at only one restaurant, and then delivering to multiple customers before refilling. The more popular restaurants would have a multiple drivers, leaving every N orders. Less popular restaurants would be grouped geographically to "share" one driver who would alternate food-pickup between the two restaurants on schedule.