3QUESTION 3 OF 3
Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
55,000
cargo ships
How to estimate it
Fermi’s official “Napkin math”
Think about how many ships leave port each day worldwide, maybe 2,000 departures. How long does an average voyage take before reaching the next port? Call it a month, 30 days. That's 30 days worth of departures all still out at sea at once.
- Ships departing ports worldwide per day
- ~2,000
- Average days at sea per voyage
- ~30
- 2,000 × 30
- ≈ 60,000
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- Global merchant fleet (>100 GT)
- ~110,000
- Cargo carriers (bulk, container, tanker, general)
- ~65%
- Share underway at any moment
- ~75%
- 110,000 × 0.65 × 0.75
- ≈ 55,000
Reference cited by Fermi: UNCTAD Review of Maritime Transport · Equasis world fleet
How close was your guess?
Your comparison will appear here.
Compare by ratio: divide the larger number by the smaller one. The closer to 1×, the better.