Estimation question

Define the size of a computer-backed system for a local Spotify-like app.

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

Tests structured estimation: breaking a vague sizing question into components with explicit, stated assumptions.

Confirm 'size' means local device storage for offline caching, the likely intent, with the interviewer.
Estimate the catalog a typical user caches, e.g. 200 songs at about 5MB each (compressed streaming quality).
Compute per-user storage: 200 x 5MB is about 1GB, plus metadata and album art, round to ~1.2GB.
If server-side capacity is meant instead, scale by concurrent offline users plus redundancy.
State assumptions explicitly (song length ~3.5 min, bitrate ~192kbps) so the interviewer can redirect.
Sanity check against a known reference, like a typical phone music cache being a few GB.

States assumptions as assumptions, not facts, and shows the arithmetic, not just a final number.
Cross-checks against a familiar reference point to catch order-of-magnitude errors.

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