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Lyft·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Apr 2026

Summary

Lyft case question, just one estimation problem about ride volume on Halloween. Short and to the point, felt more like a screen than a full round.

Questions Asked (1)

Q1

How would you estimate the total number of Lyft rides taken on Halloween?

Product Analytics & MetricsAdaptability & Ambiguity
Author's notes

I started with US population, tried to narrow down to people likely to go out on Halloween, then layered in what fraction might use Lyft vs drive or walk.

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AI HintsAI Generated

Suggested Approach

Break the problem into supply and demand sides: estimate the number of active Lyft drivers on Halloween and the average number of rides each driver completes, then multiply. Alternatively, estimate from the rider side by segmenting the population and applying adoption and ride frequency assumptions. Clearly state your assumptions and validate with a sanity check against known data (e.g., total Lyft rides per day).

Pro tip: Mention that Halloween demand is highly concentrated in the evening hours (e.g., 6 PM–2 AM) and that ride frequency per driver may be higher than average due to surge pricing and increased demand, but also note that many drivers may choose not to work that night, affecting supply.

1. Clarify scope and assumptions

Define the geographic scope (e.g., US only or global) and time frame (the entire day or just peak hours). State that you'll estimate for a typical Halloween in a mature market like the US.

2. Choose an estimation approach

Decide whether to estimate from the supply side (drivers) or demand side (riders). For a quick estimate, the supply side is often simpler: number of active drivers × average rides per driver.

3. Estimate the number of active drivers

Start with the total number of Lyft drivers in the US, then estimate the percentage who are active on Halloween night. Consider that some drivers may avoid the night due to safety or traffic, while others may be attracted by higher earnings.

4. Estimate average rides per active driver

Determine the average number of rides a driver completes during a typical shift, then adjust for Halloween-specific factors like higher demand, shorter trips, and surge pricing. For example, if a driver normally does 2 rides per hour, on Halloween they might do 3 due to increased demand.

5. Calculate and sanity-check

Multiply the number of active drivers by the average rides per driver to get the total. Compare this to known benchmarks (e.g., Lyft's total rides per day) to ensure the estimate is reasonable.

Key Points to Mention

  • Segment the day into peak (evening) and off-peak hours, as Halloween demand is highly concentrated.
  • Consider both supply (drivers) and demand (riders) factors, and how they interact (e.g., surge pricing).
  • Use known data points: Lyft's total rides per day, number of drivers, and average rides per driver.
  • Account for Halloween-specific behaviors: parties, bar-hopping, and avoiding driving after drinking.
  • Validate your estimate with a sanity check against a typical weekend night or New Year's Eve.
  • Acknowledge uncertainties and state that the estimate is a rough order of magnitude.

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