Architecture

# Answering Google Brain Teaser ” How Many Tennis Balls Fit In A Plane

We wanted to see how two experts in completely different fields would answer one such question. Pilot Anna Battison and architect Samantha Josephat both answered a brain teaser Google used to ask job candidates: How many golf balls fit into a Boeing 747? With their different professional backgrounds, the two experts approached the question in very different ways. Following is a transcript of the video.

You are watching: How many tennis balls fit in a plane

Anna Battison: Well, I hope that”s accurate. I feel like I should maybe ask somebody.

Samantha Josaphat: Um, wish me luck.

Battison: So, how many golf balls can you fit in a Boeing 747? I… I have no idea.

Josaphat: How many tennis balls? Oh, golf…wow. Wow. My first step is to dimension the size of a golf ball, which I actually don”t know.

Battison: A golf ball is, I don”t know…

Josaphat: I”ve never played golf before.

Battison: If you play tennis, a little bit smaller than a tennis ball. Josaphat: I”m gonna predict that a golf ball is 4 inches by 4 inches in diameter.

Battison: And a headrest is probably, I don”t know. Here”s my head. So let”s say it”s that big and maybe that thick. And now I”m just trying to break down the seat to figure out how many golf balls are in it. So, in this headrest, there are about 15. I”m gonna say that there are three rows of three headrests that can fit in the back portion of it. And then I”m gonna say there”s two rows of three for the bottom part. Then that gives us three, six, nine on the top, six on the bottom. 15 times 15 golf balls in each headrest. There are 15 headrests in the seat. That gives us 225 golf balls per seat.

Josaphat: I”m now attempting to draw a plane. I”m such an architect. It”s like, I gotta get it right. Oh, gosh! I”m sorry. That looks horrible. Can I just line up my wings?

Battison: This is very bad. So, you have the cabin, which is like, X1, X2 is, like, where the passenger goes with all the seats. Those are what the seats are. And then X3, which is, like, the undercarriage, which might be down here, and, you know, just where all the luggage goes.

Josaphat: When I first think about the plane and plan, what is a variable that I can replicate numerous times? And that”s the seat.

Battison: In a 747, primarily have two seats here, two seats here, an aisle, an aisle, and three seats in the middle. So that”s seven seats across in each row.

Josaphat: I will assume a Boeing 747 has about 80 rows.

Battison: So if there are 366 seats, so 366 seats in a Boeing 747, that means that 366 divided by seven would be about 52 rows.

Josaphat: Now, if I were to say a typical chair for a person is about 18 inches wide and a Boeing 747 has three aisles of seating with potentially four seats in the middle, three seats on either end, how many seats are in just one row?

Battison: I”m gonna add two seats per row because there”s an aisle here where I can add a seat, hypothetically. So if I”m adding two seats per row, that would give me 104 extra seats that I could fit in for that first layer across the bottom. There”s 470 seats on the bottom layer times 225. That gives me 105,750 golf balls.

Josaphat: So we have, six and four is 10. So we have 10 times 18. That gives us 180 inches. Then we multiply that by 80 rows. That”s 14,400 inches. That”d give me 1,200 feet. So now we would have to incorporate circulation.

Battison: Now, you gotta think about, those golf balls are really small. I”ve got so many gaps in between each seat.

Josaphat: So, if I were to relate circulation to an airplane, that would mean the aisles that go from the front and the back of the plane, the space in between the seats so that everyone can get to their seat comfortably. Battison: I”m gonna seriously ballpark this. So, across, I”ve got seven seats. Let”s say there are seven gaps where 100 golf balls can fit. That”s seven gaps in each row. So seven times 52 rows is 364. So 364 times, let”s say in each gap, 100 golf balls can fit, 36,400.

Josaphat: And, like, a typical building, in New York City”s Standard of Quality Housing, you need about 30% of circulation in a space. So what”s 30% of 1,200 feet? That”s 360 feet. That”s 360…square feet. I just realized it”s not just feet. 1,200 square feet plus 360 gives us 1,560 square feet. So that includes seats and circulation.

Battison: So, now I”m gonna picture how many layers of seats can I stack on top of each other in that gap in the cabin. I”m gonna say maybe three rows, just “cause the seats are high. So then I”m gonna do that number times three, 317,250 golf balls. That”s how many golf balls I have in three layers of seats. And that comes out as being 353,650.

Josaphat: Now we have to think about the cockpit, where the pilot is, as well as areas for meal prep and the bathrooms.

Battison: X2 is very big, right? It”s, like, 52 rows plus the space on top. So I”m gonna say there”s, you know, gotta be at least 10 that”ll fit in there. Now, maybe that”s a little bit overestimating, but I think I underestimated for the amount of golf balls anyway. So let”s just go with that.

Josaphat: So, I”m just gonna estimate 40%. “Cause typically in a building, you have to think about, 40% of the space goes to infrastructure, like mechanical systems and plumbing.

Battison: So if there are 353,650 golf balls that fit into the cabin, there would be 10 that fit in there, so that number divided by 10. That”s gonna be 35,365.

Josaphat: What”s 40% of 1,560 square feet? So now we”ll do 624 plus 1,560, and that”ll get us 2,184. So now we have the floor plan covered. And now we have to think about it in volume.

Battison: The X3 is what we have left.

Josaphat: Typical height in an apartment in New York could be around 8 to 10 feet high. And then the height of the carry-on luggage. So we”ll say 11 feet head clearance, and then we”ll add an additional two feet for the material of the plane. And so that”s 13 feet height.

Battison: I don”t actually know exactly how big a 747 is, but I would imagine very, very big.

Josaphat: Now, if we have to consider the space below where the baggage claim is, typically, someone can actually walk in that space to grab luggage.

Battison: I would say that it”s roughly the same size as the cabin or maybe even bigger.

Josaphat: And so I will just double that height and make that 26 feet. Now I will multiply 26 feet by 2,184 square feet.

Battison: The grand total is now 35,365 plus 353,650 plus 353 again, 650, equals 742,665. So that”s our grand total for a 747 that does not actually have the 366 seats.

Josaphat: So, my last step would be to divide the total cubic feet of the plane by the cubic feet that I”ve figured out for the golf ball.

Battison: But if we have an airliner, we do have those seats that can”t hold the golf balls.

Josaphat: 56,784 cubic feet divided by 12 cubic feet. That total answer would be 4,732 golf balls.

Battison: If it has 366 seats, 366 seats times however many golf balls can fit into each seat, we said was 225. So 366 times 225 would give us 82,350.

Josaphat: That really does not feel real. I”m not comfortable with that answer.

Battison: So I”m going to do this number minus this number to get our grand total for an airline 747. Gives us 660,315 golf balls.

Josaphat: Oh, I know what the problem is. I did 12 cubic feet, not 12 cubic inches. So there”s actually another step. That would be multiplying by 12. Oh, that”s funny. Which would give me 56,784 golf balls. Final answer.

Battison: I have a gut feeling that that”s way too little.

Josaphat: It may be a little bit low still. I mean, I”m gonna have to trust the math at this point.

Battison: I thought I would come out to a number that was maybe a million or so. I think I told you, a headrest is about, like, this big.

Josaphat: So if I were to go back, I”d probably tweak the size of the golf ball.

Battison: I think far more than 15 golf balls can fit into there. Maybe more along the range of 25 or 30 golf balls. In aviation, they always want you to refer back to, you know, facts. You”re always supposed to follow your checklist in an emergency. You”re supposed to rely on your instruments.

Josaphat: It did bring back the inner third grade in me, where it”s like, oh, you gotta stay up all night and figure out this math problem. Battison: Do you have an actual answer?

Alex Appolonia: Well, not exactly. We found a lot of different answers to this brain teaser. But the whole point of these questions is to show how people think. Google no longer asks these brain teasers, because they don”t predict how well someone would do at a job, but we wanted to have a little fun with it. Feel free to let us know in the comments below more brain teasers you would like to see solved, and make sure you subscribe to our channel, so you don”t miss it.