3QUESTION 3 OF 3
Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
1,030
feet
How to estimate it
Fermi’s official “Napkin math”
A 2 pound bag is about 5 cups of dry rice. How many grains in a cup? A lot, maybe 10,000. Each grain is about a quarter inch.
- Cups in the bag
- ~5
- Grains per cup
- × 10,000
- 50,000 grains × 1/4 in
- ≈ 12,500 in
- 12,500 ÷ 12
- ≈ 1,040 ft
A 900 gram bag fills about four 250 ml cups. How many grains in a cup? A lot, maybe 10,000. Each grain is about 7 millimeters.
- Cups in the bag
- ~4
- Grains per cup
- × 10,000
- 40,000 grains × 7 mm
- ≈ 280,000 mm
- In meters
- ≈ 280 m
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- Milled long-grain kernel, Roy J (Arkansas rice trials)
- 7.31 mm long, 21.1 mg
- 907 g ÷ 0.0211 g
- ≈ 43,000 grains
- 43,000 × 7.31 mm
- ≈ 314 m (1,030 ft)
- ≈
- 1,030 ft
Reference cited by Fermi: Arkansas Agricultural Experiment Station rice trials (milled long-grain kernel length and weight)
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