Best Guess · Puzzle #22 · Wednesday, October 21
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. How much electricity does an average US home use in a month, in kilowatt-hours?
The answer: about 899 kWh. Over a full year that adds up to about 10,800 kWh per household.
Napkin math - $130on a monthly electric bill
- ÷$0.15a kilowatt-hour
≈866.67kilowatt-hours
The true figure is about 899 kWh (U.S. Energy Information Administration, as of 2022). To reason it out, take $130 on a monthly electric bill, divided by $0.15 a kilowatt-hour, and you get about 870 kilowatt-hours. That lands all but on the answer, worth 9.8 out of 10 as a guess. The target is wider than it looks: every guess between 450 kilowatt-hours and 1,800 kilowatt-hours scores at least 7.0.
Source: U.S. Energy Information Administration, How much electricity does an American home use?
2. How many hot dogs do fans eat at Major League Baseball ballparks in a season?
The answer: nearly 20 million. Hot dogs are the classic ballpark food, sold in every big-league stadium.
Napkin math - 30teams in the majors
- ×81home games each
- ×10khot dogs a game
≈24.3Mhot dogs
The real answer is nearly 20 million hot dogs (National Hot Dog and Sausage Council). To reason it out, take 30 teams in the majors, times 81 home games each, times 10,000 hot dogs a game, and you get about 24 million hot dogs. It's 1.2 times too high, which as a guess would still have scored 9.2 out of 10. Because only the ratio counts, anything between 10 million hot dogs and 40 million hot dogs was worth 7.0 or more.
Source: National Hot Dog and Sausage Council, Consumption Stats
3. How many print books were sold in the US in 2025?
The answer: about 762 million. It was the second year in a row that print sales grew.
Napkin math - 330Mpeople in the US
- ×2books each a year
≈660Mbooks
The answer comes to about 762 million books (Publishers Weekly). Without looking anything up, take 330 million people in the US, times 2 books each a year, and you get about 660 million books. That comes out 1.2 times too low, and a guess that far off still scores 9.4 out of 10. Because only the ratio counts, anything between 380 million books and 1.5 billion books was worth 7.0 or more.
Source: Publishers Weekly, Print Book Sales Rose Slightly in 2025
4. How many US households are just one person living alone?
The answer: about 39.7 million. That's 29% of all households, up from 20% in 1975.
Napkin math - 130Mhouseholds in the US
- ×0.25of them with one person
≈32.5Mhouseholds
The real answer is about 39.7 million households (U.S. Census Bureau, as of 2025). On a napkin, take 130 million households in the US, times 0.25 of them with one person, and you get about 33 million households. That comes out 1.2 times too low, and a guess that far off still scores 9.1 out of 10. Any guess from 20 million households to 79 million households scores 7.0 or better, because the game only counts how many times off you are.