- An E. coli bacterium is probably around 100 nm x 10 nm x 10 nm, so that's E4 nm^3 which is E-17 mL.
- A tall water bottle is around E3 mL. Dividing,
Fermi Answer: 20
- I underestimated the size of E. coli, it's actually around 5E-13 mL.
- A tall water bottle is 5E2 mL. Dividing,
Fermi Answer: 15
How many liters of water precipitated on Earth in 2016?
Earth SA = about 10*E3^2 = E7 km^2
going to guess that average rainfall around the earth is E1 cm which is E-4 km
that would be a total of E3 km^3 of rain
That equals E12 m^3,which is E15 liters
Answer: E15
Apparently average rainfall is 100cm so E2 cm
Earth surface area is E9 (oops)
In liters, multiplying those gives 5E17, or E18
Actual answer: E18
Lets say every SAT test taker in a year used some number of SAT prep books, that if stacked (horizontally/shortest side for height), would equal their height.
How many SAT prep books were used overall that year?
EDIT: sorry for double post, was trying to edit something but accidentally quoted
Disclaimer: I feel like I misinterpreted this question; all of this could be completely wrong
The height of the stack of SAT prep books equals the height of the stack of the number of people who took the SAT. I need to find out how many people and multiply it by how much bigger a person is than a book
-The US has a population of about 3*10^8 people. Half of them are under 18, so about 1.5*10^8. I'll assume 5% of them are the age to take a standardized test. That's 7.5*10^6 people. I'll go further and assume only half of them actually take the SAT, so 3.75*10^6 people.
-Unfortunately, I have only too much experience with standardized tests. I remember a typical prep book being about 2 inches thick, so there's 6 of them in a foot. I'll assume that the average person is 5' 8" (probably an overestimate) so there's 34 books to equal a person's height.
-Multiplying 34*3.75*10^6 people gives about 124*10^6 = 1.24*10^8. Fermi answer of 8.
-1.7*10^6 people took the SAT last year.
-The Official SAT Study Guide is about 1.5 inches thick. I think it's reasonable to assume that most SAT prep books are, on average, around this thickness.
-It looks like the average 16-17 year old (the age most people take an SAT) is about 5' 7" when accounting both boys and girls
-[url=https://www.wolframalpha.com/input/?i=(1.7*10%5E6)*(67%2F1.5)]Wolfram Alpha[/url] gives a Fermi Answer of 8
How many watermelons would fit in the South China Sea?
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University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14
Adi1008 wrote:
How many watermelons would fit in the South China Sea?
- Watermelon has a volume of around 10 liters
- South China sea has around E11 liters of water
- Fermi Answer of 10.
- An average watermelon weighs 20 pounds-ish, or 9,071 grams.
- According to [url]http://www.aqua-calc.com/calculate/food-weight-to-volume[/url], it would have a volume of 13.94 liters
- South China sea has a volume of about 3.5 E9 liters.
- Dividing gives us 250-something million, so Fermi Answer of 8.
How much mouthwash, in liters, would you have to drink in order to legally be intoxicated?
talkingturtle101 wrote:How much mouthwash, in liters, would you have to drink in order to legally be intoxicated?
Going to take advantage of the fact that we are answering in fermi units here
Not sure how much alcohol is in mouthwash, but I'd say it's safe to assume its somewhere around 10%, because 5 or below is too low and 30 or above seems too high
10% alcohol is how many wines have, and the average person is drunk after about two glasses of wine. A liter can probably fill some tens of sets of two wine glasses
Final answer: -1
Apparently the average mouthwash has just about 20% alcohol. In comparison, wine has about 10%. Also it takes the average person three drinks to get drunk according to this chart I found online. A drink has about .6 fl oz of alcohol. That means it takes 1.8 fl oz of alcohol to get someone drunk, which is around 53 ml.
1/5 of a liter is 200 ml, the amount of alcohol in a liter of mouthwash. That means you have about 4 drinks in a liter of mouthwash, which means you can get wasted on .25 L of mouthwash (hey, you never know)
Final answer: -1
Actual answer
EDIT: I said 'apparently' twice, decided to fix that
i can't feel my arms wtf i think i'm turning into a lamp
voted least likely to sleep 2018, most likely to sleep in class 2017+2018, biggest procrastinator 2018
Adi1008 wrote:
Consider the partial sum of a harmonic series; that is, . What is the minimum such that the partial sum will be above 12?
Dang, that was a good question. I have no idea how to do this mathematically, but the higher n gets, the smaller the fraction is. So to get to 12, you'd probably have to go to a million, Fermi Answer of 6.
Guessing and checking on Wolfram by powers of 10 says that when n equals 100,000, the sum is 12.09, so Fermi Answer of 5
If you cut down all the trees in the world please don't try this at home, then how many Major League-size baseball bats could you make?
talkingturtle101 wrote:If you cut down all the trees in the world please don't try this at home, then how many Major League-size baseball bats could you make?
I believe there's on the order of [math]10^{12}[/math] trees on Earth. I'll assume that about E2 can be made from each tree. Fermi answer of 14.
-There are about [math]3 \times 10^{12}[/math] trees on Earth
-There isn't a definitive answer, but it looks like 50-100 bats can be made from the average tree.
-Using either 50 or 100 gives a Fermi Answer of 14.
How many textbooks do you need to equal the weight of all the water in the Pacific Ocean?
Stanford University
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14
talkingturtle101 wrote:If you cut down all the trees in the world please don't try this at home, then how many Major League-size baseball bats could you make?
I believe there's on the order of [math]10^{12}[/math] trees on Earth. I'll assume that about E2 can be made from each tree. Fermi answer of 14.
-There are about [math]3 \times 10^{12}[/math] trees on Earth
-There isn't a definitive answer, but it looks like 50-100 bats can be made from the average tree.
-Using either 50 or 100 gives a Fermi Answer of 14.
How many textbooks do you need to equal the weight of all the water in the Pacific Ocean?
Density of water = 1 gram per mL
one textbook is about 5ish kg
I remember from a previous fermi test that there are E20 gallons of water in the pacific.
A gallon is equal to 16 cups which is about 5000 mL = 5000 g = 5 kg
Answer: E20
Average weight of textbook = 4.8 pounds
Weight of a gallon of water = 8.34 lbs
Water in pacific = about 3E20 gallons
Final answer: 5.21E20 = E21 (so close :cry: )
How many letters are in George Orwell's Animal Farm?
i can't feel my arms wtf i think i'm turning into a lamp
voted least likely to sleep 2018, most likely to sleep in class 2017+2018, biggest procrastinator 2018
I think there were around 200 pages in Animal Farm, and also about 200 words per page. The average word should contain about 5 letters. Using dimensional analysis:
5*200*200 = 200,000, or 2e5
Fermi Answer: 5
So I downloaded a .pdf version of Animal Farm and converted it to a Word file. So now according to the counter, it says that there are 138,159 characters in the whole book (not including spaces) or 1.4e5 letters.
Final answer: 5
Determine the volume of water the average American will use for bathing throughout their whole life divided by the volume of the ocean.
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."
University of Texas at Austin '23
Seven Lakes High School '19
Justin72835 wrote:Determine the volume of water the average American will use for bathing throughout their whole life divided by the volume of the ocean.
Which ocean?
Stanford University
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14
