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Best Guess · Puzzle #4 · Saturday, October 3

Best Guess: the answers

Four questions, each with one true number. Here they are with their answers, how to reason each one out, and where the number comes from. Play today's Best Guess.

  1. 1. How many public schools were there in the US in the 2020-21 school year?

    The answer: 98,577. There were also about 30,000 private schools.

    Napkin math
    1. 330Mpeople in the US
    2. ÷6people for each K-12 student
    3. ÷500students a school

    ≈110kschools

    Source: National Center for Education Statistics, Fast Facts: Educational Institutions

  2. 2. How many pounds of pasta does the average American eat in a year?

    The answer: about 20 pounds. In a National Pasta Association survey, 73% of people said they eat pasta at least once a week.

    Napkin math
    1. 52weeks a year
    2. ÷2weeks per 1-pound box

    ≈26pounds

    Source: National Pasta Association, Did You Know... Americans love pasta! (key message points)

  3. 3. How many greeting cards do Americans buy each year?

    The answer: about 6.5 billion. Birthday is by far the most popular everyday card occasion, and women buy an estimated 80% of all cards.

    Napkin math
    1. 330Mpeople in the US
    2. ×15cards each a year

    ≈4.95Bcards

    Source: Greeting Card Association, Facts & Stats 2019

  4. 4. How many millimeters does a fingernail grow in a year?

    The answer: about 42 mm. Toenails grow less than half as fast, at 1.62 mm a month in the same study of young American adults.

    Napkin math
    1. 2millimeters trimmed each time
    2. ×26trims a year (every two weeks)

    ≈52millimeters

    Source: Journal of the European Academy of Dermatology and Venereology (via BioNumbers, Harvard Medical School), Growth rate of human fingernails and toenails in healthy American young adults (BNID 112380)

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