3QUESTION 3 OF 3
Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
2,300,000,000
heartbeats
How to estimate it
Fermi’s official “Napkin math”
Start with life expectancy in Mali, around 60 years, well short of the world average. Your heart beats about 70 times a minute, and there are roughly 500,000 minutes in a year.
- Life expectancy in Mali
- ≈ 60 years
- Minutes in a year
- × 525,600
- Beats per minute
- × 70
- 60 × 525k × 70
- ≈ 2.2 billion
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- Life expectancy at birth, Mali
- ≈ 60 years
- Minutes in a year
- × 525,600
- Avg resting heart rate
- × 72 bpm
- 60 × 525,600 × 72
- ≈ 2.3 billion
Reference cited by Fermi: World Bank life expectancy, Mali (60.4 years) · typical adult resting heart rate
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