Best Guess · Puzzle #35 · Tuesday, November 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. How many gallons of gasoline does the US burn through each day?
The answer: about 376 million gallons. The record was about 392 million gallons a day, set in 2018.
Napkin math - 250Mcars in the US
- ×12gallons a tank
- ÷7days between fill-ups
≈429Mgallons
The answer comes to about 376 million gallons (U.S. Energy Information Administration, as of 2023). Without looking anything up, take 250 million cars in the US, times 12 gallons a tank, divided by 7 days between fill-ups, and you get about 430 million gallons. That comes out 1.1 times too high, and a guess that far off still scores 9.4 out of 10. Any guess from 190 million gallons to 750 million gallons scores 7.0 or better, because the game only counts how many times off you are.
Source: U.S. Energy Information Administration, How much gasoline does the United States consume?
2. How many quarts of popped popcorn do Americans eat in a year?
The answer: about 14 billion. That's 43 quarts for every man, woman and child.
Napkin math - 330Mpeople in the US
- ×52weeks a year
- ×1quart (a big bowl) each a week
≈17.2Bquarts
The answer comes to about 14 billion quarts (The Popcorn Board, for 2016 to 2020). To reason it out, take 330 million people in the US, times 52 weeks a year, times 1 quart (a big bowl) each a week, and you get about 17 billion quarts. The estimate is 1.2 times too high, close enough to score 9.1 out of 10. Any guess from 7 billion quarts to 28 billion quarts scores 7.0 or better, because the game only counts how many times off you are.
3. 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 - 2millimeters trimmed each time
- ×26trims a year (every two weeks)
≈52millimeters
The answer comes to about 42 mm (Journal of the European Academy of Dermatology and Venereology, as of 2010). Without looking anything up, take 2 millimeters trimmed each time, times 26 trims a year (every two weeks), and you get about 52 millimeters. It's 1.2 times too high, which as a guess would still have scored 9.1 out of 10. Any guess from 21 millimeters to 84 millimeters scores 7.0 or better, because the game only counts how many times off you are.
4. How many windows does the Empire State Building have?
The answer: 6,514 windows. The exterior also uses 10 million bricks, along with Indiana limestone, granite, aluminum and stainless steel.
Napkin math - 100floors in the building
- ×60windows around each floor
≈6,000windows
The real answer is 6,514 windows (Empire State Building). To reason it out, take 100 floors in the building, times 60 windows around each floor, and you get about 6,000 windows. The estimate is 1.1 times too low, close enough to score 9.6 out of 10. Any guess from 3,300 windows to 13,000 windows scores 7.0 or better, because the game only counts how many times off you are.