Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
30
days
How to estimate it
Fermi’s official “Napkin math”
Shanghai to Rotterdam by sea is about half way around the world, say 20,000 kilometers. How fast does a giant cargo ship go? Maybe 30 km/h, about bike speed, which is roughly 700 kilometers a day.
- Half way around the world
- ≈ 20,000 km
- 30 km/h × 24 hours
- ÷ 700 km a day
- 20,000 ÷ 700
- ≈ 29 days
Shanghai to Rotterdam by sea is about half way around the world, say 12,000 miles. How fast does a giant cargo ship go? Maybe 20 miles an hour, which is roughly 500 miles a day.
- Half way around the world
- ≈ 12,000 miles
- 20 mph × 24 hours
- ÷ 500 miles a day
- 12,000 ÷ 500
- ≈ 24 days
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- Shanghai to Rotterdam via Suez
- ≈ 10,600 nautical miles
- Non-stop at 16 knots
- ≈ 27 days
- Typical scheduled service, with a few port calls
- 28 to 32 days
- ≈
- 30 days
Reference cited by Fermi: Notteboom, Pallis & Rodrigue, Port Economics, Management and Policy: Routing Options between Shanghai, Rotterdam and New York
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.