Proofreading Mistakes
If proofreader 
finds 
mistakes and proofreader 
finds 
mistakes, 
of which were also found by , how manymistakes were missed by both and ? Assume there are a total of 
mistakes, so proofreader finds a Fraction
of all mistakes, and also a Fraction 
of the mistakes found by . Assuming these fractions are the same,then solving for gives
The number of mistakes missed by both is therefore approximately
References
Pólya, G. ``Probabilities in Proofreading.'' Amer. Math. Monthly, 83, 42, 1976.
- Solidus
- Solitary Number
- Soliton
- Solomon's Seal Knot
- Solomon's Seal Lines
- Solomon's Seal Polygon
- Solvable Congruence
- Solvable Group
- Solvable Lie Group
- Soma Cube
- Somer-Lucas Pseudoprime
- Sommerfeld's Formula
- Somos Sequence
- Sondat's Theorem
- Sonine Polynomial
- Sonine-Schafheitlin Formula
- Sonine's Integral
- Sophie Germain Prime
- Sorites Paradox
- Sorting
- Sort-Then-Add Sequence
- Source
- Sous-Double
- Souslin Set
- Souslin's Hypothesis