Estimation question
Estimate the number of cars sold through cars24 since the first lockdown of COVID19 (March 2020).
- Cars24
- Estimation
- Hard
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What this question tests
Structured estimation over a defined time period, combining market context with growth assumptions.
How to approach it
- Clarify scope: total used cars sold through Cars24 from March 2020 to the interview date, roughly 5 to 6 years.
- Estimate a starting monthly sales volume for Cars24 around the 2020 lockdown, using general awareness of the used-car platform market in India.
- Assume a growth trajectory, since platforms like Cars24 scaled significantly post-pandemic as used-car buying moved online.
- Break the period into rough phases (2020 lockdown dip, 2021-2023 growth, 2024-2026 maturity) with a different monthly estimate for each.
- Sum the estimated monthly volumes across each phase times the months in that phase to get a cumulative total.
- State the result as a wide range, acknowledging high uncertainty in a private company's growth curve.
What a strong answer includes
- Breaks the multi-year period into distinct growth phases instead of a naive flat monthly average.
- States the starting and ending monthly volume assumptions explicitly, e.g. 5,000/month in 2020 growing to 40,000/month by 2026, marked as assumptions.
- Shows the summation logic across phases rather than one multiplication.
- Acknowledges the estimate's wide uncertainty band given no public data on a private company.
Common mistakes
- Using one flat monthly rate across a 5-6 year period with major real-world growth.
- Ignoring the 2020 lockdown's likely initial dip in used-car sales before recovery.
Likely follow-up questions
- How would you validate this estimate against public information?
- Which phase of growth are you least confident about?
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Learn the skill behind it
Chapters of the AI PM course that teach what this question tests.
- Chapter 2: Data fluency: SQL, logs, and reading the truth yourself
- Chapter 9: Prove it paid off: outcomes, economics, and pricing
- Chapter 14: Get the job: the AI PM interview loop