I espeically liked:

Lush: Went the route of using volume to calculate.

Banquo: Added to that by using water to calculate these volumes.

Devon Davidson: Went the extra mile to subtract the displacement of the bus itself, leaving only the SPACE in the bus.

But I think the answer that really deserves a gold star is D4's:

"

*I made a really long comment, it was longer than your post. I'm shortening it now: I figured about 700 golf balls could take up the matter I take up (just a guess) and worked around that, filled up the bus in layed down me's in a bus of say 22 seats, included the drivers seat plus the extra room on the bus and figured the number inclined towards 300k golf balls. That seems wrong, so I think I underestimated the amount of GB's, but it would still be my initial guess"*

Now I'm curious to hear the extra long answer you originally had!

Anyway, sorry if I left your name out but everyone did very well and came up with some interesting methodologies (remember, it's not the final answer I'm interested in; it's the methodology!)

Here's one from Vault.com, which specializes in business interviews, that totally blew me away:

*Let's assume that the volume of a ping-pong ball is three cubic inches. Now let's assume that all the seats in the plane are removed. We'll say the average person is six feet high, one foot wide and one foot deep. That's 6 cubic feet, or 10,368 cubic inches. (One cubic foot is 12x12x12 inches, or 1,728 cubic inches.)*

*Okay, so a 747 has about 400 seats in it, excluding the galleys, lavatories, and aisles on the lower deck and about 25 seats on the upper deck. Let's assume there are three galleys, 14 lavatories, and three aisles (two on the lower deck and one on the upper deck), and that the space occupied by the galleys is a six-person equivalent, by the lavatories is a two-person equivalent, and the aisles are a 50-person equivalent on the lower deck and a 20-person equivalent on the upper deck. That's an additional 18, 28, and 120 person-volumes for the remaining space. We won't include the cockpit since someone has to fly the plane. So there are about 600 person-equivalents available. (You would be rounding a bit to make your life easier, since the actual number is 591 person equivalents.)*

*In addition to the human volume, we have to take into account all the cargo and extra space - the belly holds, the overhead luggage compartments, and the space over the passengers' head. Let's assume the plane holds four times the amount of extra space as it does people, so that would mean extra space is 2,400 person-equivalents in volume. (Obviously, this assumption is the most important factor in this guesstimate. Remember that it's not important that this assumption be correct, just that you know the assumption should be made.)*

*Therefore, in total we have 3,000 (or 600 + 2,400) person-equivalents in volume available. Three thousand x 10,368 cubic inches means we have 31,104,000 cubic inches of space available. At three cubic inches per ball, a 747 could hold 10,368,000 balls. However, spheres do not fit perfectly together. Eliminate a certain percentage - spheres cover only about 70 percent of a cube when packed - and cut your answer to 7,257,600 balls.*

The last, extra step there of reducing 30% is what really makes this answer stand out; taking a largely vague estimate and making peculiar adjustments as that to "fine tune" it. Anyway, back to our regular scheduled programming:

*A bus full of people travels from Vancouver to Burnaby. No one gets off the bus for the entire duration of the ride. But when it reaches its destination, not a single person is left on the bus. How come?*

Because they get off when the bus is stopped.

ReplyDeleteNot a single person is left... behind? Meaning everyone is still in the bus. ;)

ReplyDeleteWhy do I find this so amusing? Oh dear gosh, wtf is wrong with me..... I actually can't stop laughing. -_-

ReplyDeletenoone wants to travel to burnaby? ;)

ReplyDeleteThey get off when the bus is stopped. That or Burnaby isn't the destination, it's a stop along the way to the destination.

ReplyDeleteSeems like someone spent a bit too much time looking at golf-balls :|

ReplyDelete"

ReplyDeleteThe last, extra step there of reducing 30% is what really makes this answer stand out; taking a largely vague estimate and making peculiar adjustments as that to "fine tune" it. Anyway, back to our regular scheduled programming:

"

That is because of angles. Angles would widely decrease the average volume of displaced ballspace.

I'll figure it out... later

ReplyDeleteThe longer explanation was just my calculations, 10 golf balls to each foot, 40 or so from ankle to knee, etc, until reaching the rest of my body by filling it up with my legs or in cases like my head, with my feet, then it was the calculation of stacking the me's and how that would work, 3 me's in the floor area followed by 6 (totaling 9) to reach the top, and then another 6 from the seat to the roof, continued that throughout the row between the seats and then the drivers seat which was more cluttered than a normal seat and the entrance to the bus, along with all the math I did inbetween. I then figured that if the mass of me's were magically turned into real golf balls, the pile would seap lower than what it had reached, so I made an estimate on golf balls to add to reach closer to the top of the bus, I was really lazy by that point. Note that, it was actually really simply done, and that's because I have an intense hate for math. I only figured I'd do it in case in the future I DO get an interview with a similar question. and the bus thingy stumps me. I need to focus more on these things.

ReplyDeleteiam still failing at every single one of them :(

ReplyDeleteThis ping pong one is a real question asked by google when you apply there.

ReplyDeleteI think all the people left were married.

ReplyDeleteEveryone on the bus is dead

ReplyDeletebus is empty?

ReplyDeleteIf "not one" got off the whole trip, then "everyone" could have gotten off. As long as it wasn't one single person.

ReplyDeleteNo passengers ever got on the bus?

ReplyDeleteI just realized the first sentence says a bus full of people, so disregard my last comment, lol. Maybe because...everyone got off at Burnaby

ReplyDeletelol I missed yeaterday but I would probably have come up with an answer that would involve melting down the golf balls for maximum space use :P

ReplyDeleteAs for this puzzle. Sounds like a couples retreat to me ;)

im puzzled

ReplyDeleteyup they all died D:

ReplyDelete