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Best Guess · Puzzle #12 · Sunday, October 11

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 change-of-address requests does the US Postal Service process on an average day?

    The answer: about 71,000. Meanwhile the Postal Service also adds about 6,000 brand-new addresses to its network every day.

    Napkin math
    1. 130Mhouseholds in the US
    2. ÷6years between moves
    3. ÷365days a year

    ≈59.4kaddress changes

    Source: United States Postal Service, Postal Facts - One Day

  2. 2. How many pounds of potatoes (fresh, frozen fries, chips and all) did Americans eat in 2022?

    The answer: about 36.9 billion. Most of it is processed, and frozen potatoes are the biggest share.

    Napkin math
    1. 330Mpeople in the US
    2. ×52weeks a year
    3. ×2pounds of potatoes each a week

    ≈34.3Bpounds

    Source: USDA Economic Research Service, Food Availability (Per Capita) Data System: Vegetables (all uses), Potatoes

  3. 3. How many gallons of water does the US use just for showering in a year?

    The answer: nearly 1.2 trillion gallons. The EPA says that's enough to supply the water needs of New York and New Jersey for a year.

    Napkin math
    1. 330Mpeople in the US
    2. ×15gallons a shower
    3. ×260showers a year each (5 a week)

    ≈1.29Tgallons

    Source: U.S. Environmental Protection Agency (WaterSense), Showerheads

  4. 4. The Boston Marathon runs 26.2 miles from Hopkinton into Boston. How many spectators line the route?

    The answer: more than half a million. They cheer on more than 30,000 official runners.

    Napkin math
    1. 26miles of course
    2. ×2sides of the road
    3. ×10kpeople a mile on each side

    ≈520kspectators

    Source: Boston Athletic Association, 2019 Boston Marathon Injects More Than $200 million into Greater Boston Economy

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