Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
124,000
rubber duckies
How to estimate it
Fermi’s official “Napkin math”
A 40-foot shipping container holds about 2,400 cubic feet inside. A rubber duck is small but round, so how many pack into one cubic foot once you count the gaps? Maybe 60.
- Container interior
- ~2,400 ft³
- Ducks per cubic foot (with gaps)
- × 60
- 2,400 × 60
- ≈ 144,000
A 40-foot shipping container holds about 68,000 liters inside. A rubber duck is small but round, so how many pack into a liter once you count the gaps? Maybe 2.
- Container interior
- ~68,000 L
- Ducks per liter (with gaps)
- × 2
- 68,000 × 2
- ≈ 136,000
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- 40ft container interior volume
- ≈ 67.7 m³ (2,390 ft³)
- Volume of one bath-size rubber duck (~9 cm, envelope)
- ≈ 300 cm³
- Packing efficiency (irregular hollow toy shapes)
- × 0.55
- 67,700,000 ÷ 300 × 0.55
- ≈ 124,000
Reference cited by Fermi: ISO equipment spec sheets · Rubber duck retail dimensions
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