Estimation question

Count the number of soccer balls that can be accommodated on a soccer field.

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

Whether the candidate can build a clean geometric estimate using area assumptions and stated packing logic.

State the field dimensions: a standard soccer field is roughly 105 by 68 meters, giving an area of roughly 7,140 square meters.
Estimate a soccer ball's footprint: a ball is roughly 22 centimeters in diameter, so assume each ball occupies a square of about 0.3 by 0.3 meters for spacing, or 0.09 square meters.
Divide total area by footprint per ball: 7,140 divided by 0.09 gives roughly 79,000 balls if packed flat in a single layer.
Adjust for realistic packing inefficiency (balls are round, not square, so true packing density is lower), applying roughly a 20 percent reduction.
Land on a final estimate of roughly 60,000 to 65,000 balls for a single flat layer, and note that stacking would multiply this further if allowed.

States field and ball dimensions explicitly before calculating, rather than jumping to a guessed final number.
Adjusts for real packing inefficiency instead of assuming perfect square-tile packing of round objects.
Clarifies the single-layer assumption and notes how stacking would change the answer if the interviewer wants that extension.

Using square packing without adjusting for the fact that circles don't tile perfectly.
Not stating the field or ball dimension assumptions clearly before calculating.

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