Estimation question

Estimate the number of electric vehicle charging stations in the US.

Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.

What this question tests

Fermi estimation using a plausible per-vehicle ratio, built from a defensible base number.

State you'll estimate via the number of registered EVs and a typical vehicles-per-charging-station ratio.
Estimate US EV count, e.g. assume roughly 3 million EVs on the road.
Assume a rough ratio, e.g. 1 public charging port per 15 to 20 EVs.
Multiply to get an estimated number of charging ports.
Adjust for private home chargers, which dominate but aren't counted as public stations.
State the final range and sanity-check the order of magnitude.

Anchors on a defensible input, EV registration count, rather than guessing stations directly.
States the ports-per-EV ratio explicitly as an assumption, not a fact.
Distinguishes public charging infrastructure from home chargers, which dominate but aren't 'stations' in the usual sense.
Gives a final range with visible math rather than one over-precise number.

Guessing a raw number with no supporting math or stated assumptions.
Conflating public charging stations with the much larger count of private home chargers.

Chapters of the AI PM course that teach what this question tests.