Estimation question

How much storage and bandwidth do we need for Google Drive service next year?

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 you can build a bottom-up estimation model with clear assumptions and sanity-check the result against a known reference point.

Confirm scope: total incremental storage and peak bandwidth needed for Google Drive over the next 12 months, not current total.
Estimate active users: assume 1 billion Drive users, with 20 percent active uploaders in a given month, about 200 million.
Estimate storage per active uploader: 2 GB of new content per month on average, blending light users and heavy media uploaders.
Compute incremental storage: 200 million times 2 GB times 12 months, roughly 4.8 exabytes of new storage for the year.
Estimate bandwidth from peak concurrent uploads and downloads, assuming 5 percent of active users transferring simultaneously at 1 MB per second each.
Sanity check against Google's known scale, cloud storage growth is typically in the exabyte range annually, so the estimate is directionally reasonable.

Separates storage, a capacity problem, from bandwidth, a peak-throughput problem, since they drive different infrastructure investments.
States each assumption as a number, not a vague range, so the interviewer can challenge a specific input.
Sanity-checks the final number against a known industry scale rather than presenting it as exact.

Conflating total storage in use with incremental growth needed, which produces wildly different numbers.
Skipping the sanity check, leaving an estimate that could be off by orders of magnitude with no way to catch it.

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