Quiz: which cup will fill first?


According to the most agreed upon answer on various sites, once this is pointed out, PHenry is the first to answer correctly.

I have to warn you, people are going to argue their answer and say others are bogus, or unfair. But after I got this wrong (lol) I have to agree with one of the explanations.


120 Comments on Quiz: which cup will fill first?

  1. none. By the time every pathway and reservoir is full, including the ones with blockages there is not enough coffee to reach even the only unblocked cup 5.

  2. 20-some years ago I coached a high school volleyball team, and the girls would occasionally play a game on the bus. One girl would make a gun with her fingers (probably would cause a school shutdown these days), point at various others as she said ‘bang click click bang click bang bang’ in some random order. ‘Who’s dead?’ Then the others would hazard a few guesses and she would tell them who. Of course everyone tries to figure out the order of bangs and clicks. But the answer is that the first person other than the ‘shooter’ who speaks is dead.

    My point is that this is a game of ‘I made a set of rules, and until you understand the rules you are on the outside.’ I hate those games. Same reason why I hate David Lynch films – he has a different universe in which he makes up the rules, so you are constantly frustrated (or intrigued if you’re into that crap).

  3. Cup 4.

    The pipe that leads to cup 4 is at the bottom of the tank it’s connected to.

    Cup 9 won’t start to fill until Cup 5 is full and the coffee level reaches its pipe, which is higher on the tank.

    The right side has two tanks, one of which is directly beneath the other and has no pipes leading out.

    The pipe leading to cup 7 is at the halfway point on the upper tank, which means it won’t get any coffee until the lower tank is full, and the upper tank is half full.

    Cup 5 won’t get any coffee until both tanks and cup 7 are full. (I’m assuming there’s some automatic cutoff system and the coffee won’t keep flowing once the cup is filled.)

    Conclusion: Cup 4 will fill first because it has the most direct connection to the filling tank, and no time is wasted while a tank fills completely or partially.

    What’s more, the pipe for the tanks on the left side of the fill tank is lower than the pipe for the tanks on the right side.

    Applause and praise for my genius are freely accepted.

  4. Welcome to the interweb Furhat! This one has been out on social media for so long that I thought everyone, except maybe a few in Kazakhstan, would know the answer.

  5. I have to beat this into the new graduates because all they know is 3D. They think that just because they can model something in virtual space that it can be magically made perfect…
    Did you do your tolerance stack up?
    What’s that?…

  6. Well, I only noticed two of the three blocked “pipes” so my answer’s wrong.

    But in a real world situation, none of the drawing’s cups would fill before the cup I’m holding in my hand. What moron would waste perfectly good coffee on a stupid test question without taking some for himself first?

  7. The other dumb thing they do is model something at about 100:1 scale. I ask them if it can be made. They say “sure, it’s on the screen ain’t it?” Then I say “print it out in full scale” and it looks like a dot on the page.

  8. “Can he understand the GDT callout and make the part?”

    That what I do. But in order to get complexed Geometry through quality departments I need to understand it better than they do. And it can get sporting believe me.

  9. A friend of mine had a test in college just before Christmas break. The test had one question. My friend was in a hurry and answered “God only knows – Merry Christmas!”.
    When he returned after break, he got the paper back. The prof wrote, “God gets an A, you get and F – Happy New Year!”.

  10. #4 is the only one that will fill, then overflow.

    The only way that other cups will fill is if the 4 & 9 junction “pipe” flow rate is greater than the maximum overflow rate of #4.

  11. My question is, who wants to know, why do they want to know, if I do answers there question, can that answer be used in a court of law, can my answer be used to keep from get any type of Government Job or Security clearance?
    If not, my answer is #5. Only tube that has an open tube straight to cup.

  12. I’m on my second cup.

    I’m gonna be all assholey Alex Trebekish because I have the answer card: Some of you got it right. Some of you got it part right. Sorta. BFH will be along shortly to give you the answer. 😀

  13. #9

    It exhibits the path of least resistance, in my opinion. 4 and 7 are blocked.

    Of course, since I’m usually wrong about this I’ll bet it’s cup#5 since it makes no sense to me.

  14. I don’t believe PHenry is right.
    You have no idea the volume of any of the cups since this is only a 2D exercise. Therefor,e you cannot say with any certainty that the coffee decanter will empty before any will fill.

  15. I will try again….
    You have no idea the volume of any of the reservoirs since this is only a 2D exercise. Therefore, you cannot say with any certainty that the coffee decanter will empty before any will fill.

  16. @jethro. I’m always right. Except when I’m not.
    Yes. I agree that it was a two dimensional representation so there was no way to know the volume capacity of any pipe or reservoir. Plus, there would be a point where capped pipeways would not accept liquid as the trapped air would prevent it.

  17. Upon further review…. Jethro makes a valid point.

    You’re out of order, this post is out of order, and the guy who made this should go right to f*ckin’ jail!!!

  18. I just three D printed one, made it .125 thick with .031 walls. There was coffee left over and #5 is the only one that filled up. Now I gotta find that damn mop.

  19. Luckily Elana Kagan has agreed to participate in this experiment. Hopefully we remember to bring the wood. Sorry, that was poorly phrased. Hopefully we remember to bring the lumber. Ah shit. At least we aren’t laying pipe.

  20. Never trust a Paki. I can tell you some stories. Some really good stories. Indian engineers are not much better. YOU GET WHAT YOU PAY FOR. So don’t bust my balls about a lack of engineers. I’ve seen it. Point MoFo blank.

  21. @ Brad ~ don’t forget the Germans … can’t tell you how many time I’ve heard about software, hardware, equipment, platforms, etc. … “Powerful .. very Powerful!”


    I’ve worked with a lot of Germans. Very smart minds. Very very disciplined. Same as the Japs and Chicoms. ZERO creativity. America is a great experiment. Here’s the thing about America. America promotes abstract original thinking. It’s so awesome. Creativity. Sadly they are trying to kill it.

  23. @Brad ~ don’t get me wrong, my dad’s side of the family is solid German stock … just a lot of arrogance … (like me 🙂 ) that gets in the way of ‘flexability’

    I’m thinking you and your family tree are American Germans. An asset to America.

    However I’m an American cur and have made assholes out of many disciplined ass holes.

  25. “Fuck you, Brad. Your right. 9 is blocked. I didn’t see that.”

    LOL Tsunami. You get a four wheeler yet? I know Wyoming can get cold. But Northern California was all the way down to 48 degrees this morning. Highs only reached 68. This shit’s brutal. LoL Lol Lol. Hang in there buddy.

  26. Brad,

    Got the snow tires and the studs for the ice traction. This first winter is gonna be a test, but it’ll still be easier than dealing with this boring-ass job I have right now. It’s a struggle to drudge through an 8 hour shift.

    …and I miss my family badly.

  27. There isn’t enough cofeve in the carafe to fill ANY of the cups … so it doesn’t really matter.

    You see, in the Great Cosmic Scheme of Things, some things are simply, heuristically, psycho-socially, irreducible.

    “Nothing really matters;
    any one can see …
    Nothing really matters
    to meeeeeeeee !!!!”

    I wrote that some years ago for some friends of mine and it kinda sums up the whole thing.

  28. @ Moe Tom – I just saw your two comments! How sweet of you! I like Salted Caramel in my latte – just in case someday we neet – you just never know. 😀

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