← DoubleVerify Interview Insights
Break the problem into manageable components: estimate the number of buildings in NYC, then estimate the average number of windows per building, and multiply. Clearly state your assumptions and use round numbers to simplify calculations, focusing on demonstrating logical reasoning rather than getting an exact answer.
Pro tip: Acknowledge that this is a Fermi problem and that the process matters more than the precise number; mention that you would validate your estimate with real data if available, showing you understand the limitations of pure estimation.
Define what counts as a window (e.g., building windows only, excluding vehicles) and what area of NYC to include (all five boroughs). This shows you think critically about the question.
Use known statistics or reasonable assumptions: NYC has about 1 million buildings (or estimate from population and average household size). Break down by building types (residential, commercial, industrial).
For each building type, estimate the average number of windows. For residential, consider average number of units per building and windows per unit; for commercial, consider floor area and window density.
Multiply the number of buildings by the average windows per building for each category, then sum to get a total estimate. Use round numbers for simplicity.
Assess whether the result seems plausible (e.g., compare to population or known building counts). If time permits, refine assumptions or mention alternative approaches.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.