✏️ Explanatory Question
Do not draw anything yet. Narrow the problem out loud.
1. Repeat and narrow. "Uber covers rider matching, pricing, payments, driver onboarding and maps. I will design the core ride request and matching flow, and treat payments and maps as external services. Does that work?"
2. Core functional list (3 only). Rider requests a ride from A to B; system matches a nearby available driver; both parties see live location during the trip.
3. Scale assumptions, proposed not asked. "I will assume 100 million users, 5 million daily rides, 1 million active drivers sending location every 4 seconds." That last number is the one that matters - it is about 250,000 location writes per second, which dominates the whole design.
4. One or two non-functional targets. Matching within 5 seconds; location updates are lossy-tolerant but ride state must never be lost.
5. Call the hard part early. "The interesting problems here are geospatial indexing for nearby driver lookup, and the very high write rate of location pings. I will spend most of my time there."
Naming the hard part in minute five is what separates a senior answer from a junior one.