← MasterClass Interview Insights

MasterClass·Product Manager·Onsite - Product Sense / Strategy·Intermediate

IntermediatePrefer not to say
Apr 2026

Summary

Got a market sizing question at MasterClass, pretty standard stuff for a product or strategy role. Nothing too crazy but it's the kind of question that feels easy until you're actually doing it out loud.

Questions Asked (1)

Q1

How many gas stations are there in California?

Product Analytics & MetricsAdaptability & Ambiguity
Author's notes

I went top-down: California population, average household size, cars per household, how often people fill up, then backed into station count by capacity.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Break the problem down using a top-down estimation approach: start with California's population, estimate the number of vehicles, and then determine how many gas stations are needed to serve them. State your assumptions clearly and calculate step by step, focusing on logical reasoning rather than the exact number.

Pro tip: Acknowledge that this is a Fermi problem and that the process matters more than the precise answer; show your work and sanity-check your final number against known benchmarks (e.g., ~10,000 stations in California).

1. Clarify the scope

Confirm whether the question refers to all gas stations (including those at grocery stores) or only standalone stations, and whether it's for personal vehicles or all vehicles. This shows attention to detail.

2. Estimate California's population

Use a known figure: approximately 40 million people. Then estimate the number of vehicles: assume about 2 people per household and 1.5 vehicles per household, or simply 0.8 vehicles per capita, yielding ~32 million vehicles.

3. Estimate demand per gas station

Calculate how many vehicles a typical gas station can serve. Assume each station has 8 pumps, each pump serves 2 cars per hour, and operates 12 hours a day, serving ~200 cars per day. Alternatively, use average fuel sold per station per day.

4. Calculate number of stations

Divide total vehicles by the number of vehicles served per station per day, adjusting for frequency of refueling (e.g., once a week). For example, if each vehicle refuels weekly, total weekly refuels = 32M, and if each station serves 1,400 cars per week (200/day * 7), then stations = 32M / 1,400 ≈ 22,857. Sanity-check against known data.

5. Sanity-check and refine

Compare your estimate to known benchmarks (e.g., California has about 10,000 gas stations). If off, adjust assumptions (e.g., higher throughput per station) and explain discrepancies.

Key Points to Mention

  • Top-down estimation using population and vehicle ownership rates
  • Assumptions about vehicle refueling frequency (e.g., once per week)
  • Throughput of a typical gas station (pumps, hours, cars per hour)
  • Sanity-checking against known data or industry averages
  • Acknowledging that the exact number is less important than the logical process
  • Considering factors like electric vehicles, public transit, and urban vs. rural differences

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.