Jump to content
BrainDen.com - Brain Teasers

All Activity

This stream auto-updates     

  1. Today
  2. Yesterday
  3. tmaker


    ok..sorry for a start...just a 'stupid' question...something like that..( it's all about lottery ) WHAT ARE THE ODDS ? basically we can find on the net the odds for 6/45,6/49 and so on including the Powerball and the rest... so, my question is this..I will try to be as clear as possible..sorry if it sounds confusing... ( i did searched on the net and one says a 'math' guy gave the probability of billions of combination...yes...billions..) but I do not think so... so, here we go..i came across a lottery game.. you choose 1 set of 4 digits from 0000 to 9999 = odds of you hitting the 1st prize ( one prize ) is 1/10,000 ...right ? example : you chose 1234 ...from 0000 to 9999 ------------------------------------------------------------ now this gets interesting; they have a game where you choose 2 sets of 4 digits, eg. 1234 + 5678 this is called a pair... so, you will have 1234 ( from 0000 to 9999 ) we will call SET A + 5678 ( from 0000 to 9999 ) we will call SET B basic layman calculation WILL BE : 10,000 x 10,000 = 100 million possibility ?... yea ? not exactly... cos we will have same pair as we go along.. so , like this... SET A SET B ( for 0000 ) SET A SET B ( for 0001 ) and so on.... 0000 + 0000 = 1 pair 0001 + 0000 <---- same as 'x' 0000 + 0001 = 1 pair <--- same as 'x' 0001 + 0001 so for SET A alone for '0000' + 9,999 of SET B , we will have 10,000 PAIRS... and so on.. but looking at 'x' , it' the same , so it count as the SAME COMBO... so, less than 100 millions cos you take out the SAME combo... 1ST QUESTION so, what are the odds ? -------------------------------------------------------------------------- NOW.......IT'S GETS MORE INTERESTING ... for you to hit Jackpot 1 you need your selection of 1234 + 5678 ( your pair ) to come out in either the 1st, 2nd or 3rd prize... example : 1st Prize - 1234 OR 1st prize - 1234 2nd prize - 5678 2nd prize - 8817 3rd prize - 8817 3rd prize - 5678 as long as your 'pair' appears in the to 3 prizes.. odds are different again, right ? so, anyone can help ? lol !!!!
  4. Last week
  5. There are three of them today. All three are different from each other. One of them thought to date back to ancient Rome. There are precious stones on another. What is the name of the one with precious stones?
  6. Earlier
  7. Fun

    Think about these

    The answer to all of these silly fooleries: 1. If there's a bullet that can shoot through any barrier and there's an armor that nothing can get through, then the bullet won't get through it, because she can go through any barrier, but not any armor, and that armor, nothing can get through it, and nothing is void, or more precisely the absence of any existence, but nothing is still existing! So nothing CAN get through the armor, but not the bullet, because you said that she can go through any barrier, but not any armor. 2. The fountain of eternal life gives eternal life, making you able to age forever without your body stopping working because he's too old, not invincibility to any damage that can happen to your body, and drowning is water damaging and clogging your lungs until you can't use them to breath anymore, lack oxygen, and die, so you're able to live as much as you want, but not survive any kind of trauma or damage. 3. If you don't accept the mission, then ok, but if you accept the mission, you failed the mission, but you still advanced to somewhere in the mission, you made progress in a way, because even being bad still advances you in something, maybe towards prison, but still! 4. If the girl killed her grandmother after she gave birth to one of her parents, then she is still born. 5. The morning, the temperature is 0°, but in the night, it gets colder, so -1°, -2°, -3° or less, so tomorrow it will be either -2°, -4°, -6° (even decimals)... etc. 6. You just answer «truthfully (yes or no)». 7. First, let's say the car is properly equipped to resist such speed. If you're in a car like this and go the speed of light, the first photon that comes out will stay motionless, in the same spot it appeared, and no more photons will come out, because there is already one occupying the "appearing spot". And finally 8. He just creates a stone with a negative weight that has a smaller number than his own weight, which can float, so if he lifts it up, the stone is only floating, not being lifted, so it doesn't count as "lifting", and if he holds it in his hands while its over the ground, he will make it go down, so the stone is being "lifted "up"", in its own dimension of logic. If you think I'm wrong, rethink it, and you'll see.
  8. um........ all 12 of them NOT 1
  9. all months have 28 days because all of them have at least that many.
  10. Using a famous BIM software (stating with a R) i found 56 m3 and by hand, I can't get closer than 61 m3 (by approximating the whole complex void as a simple rectangular pyramid)
  11. Hello all! I was in practicing BIM (building information modeling) at school when our teacher told us than crazy shapes aren't an issue anymore when it comes to determinating a volume since we can rely on computers. We now just have to draw it in 3D and softwares can give us the answer we need. I was curious about how it was done before all that. Here's an example : From above, a rectangular shape. Corners at the same higher height are merging into a point at a lowest height. See attached picture. I tried to figure the volume by hand considering a whole rectangular parallelepiped from which I substracted parts of rectangular based pyramids. Well, turns out I can't manage do find the good answer. Can anyone? I doubt it will bother you as much as it did bother me. Cheers2553_001.pdf
  12. it kind of sounds like a hole puncher or stapler. you can hear it going down through something or into something.
  13. I was thinking the Father could be 42 and his son 24, there for together makes 66 and 42 backwards is 24. the father must of had his son (if in fact it is his son?) at the age of 18.
  14. Weedle013

    7 is Split-second timing
  15. I've previously written a nice word puzzle script, which takes in a huge list of words, and creates a list of anagram "siblings". One of the special functions is to find, for each word length, the largest anagram set of siblings.
  16. My guess is, “Will you NOT marry me?” This yes/no question works because either way you answer it, the answer is “no”, ensuring you do not marry the middle daughter: “no, I will not marry you” and “yes, I will not marry you”
  17. Not sure if contractions count but I got: A I Am I’m An In
  18. loved the an elephant in a refrigerator puzzle... Have seen another variant here- https://youtu.be/kXKeLBwSzPI
  19. there is a way however to permute through all possibilities by swapping two letters. ABC -> ACB -> BCA -> BAC -> CAB -> CBA ABCD -> ABDC -> ACDB -.> ACBD -> ADBC -> ADCB -> BDCA -> BDAC -> BADC -> BACD -> BCAD -> BCDA -> CBDA -> CBAD -> CABD -> CADB -> CDAB -> CDBA-> DCBA -> DCAB -> DBAC -> DBCA -> DACB -> DABC
  20. This will only work if there were exactly 10 of each colour.
  21. Ah-ha! The first toss is irrelevant. Thus the second player has the best chance ...
  22. There's a way to understand that the odds are equal for both bowls without doing any math (for both the one poison apple = death and the two poison apples = death variants). Label the apples in each bowl as either common (C) or rare (R), so each bowl has CCCRR. For bowl 1, the common apples are poisonous and the rare apples are not. For bowl 2 the opposite. When you choose the apples that you are going to eat (from whichever bowl) you are going to divide the apples into two groups - those you will eat, and those you won't. In the one apple = death variant, the only way to survive is to divide the apples into two specific groups: CCC in one group and RR in the other. This is true for bowl 1 and bowl 2 - which means that the probability is the same for both. For bowl 1, you will then eat the two apples (both rare/nonpoisonous). For bowl 2, you will then eat the three apples (all common/nonpoisonous apples). In the two apples = death variant, you will only die in one way: if you divide the apples such that the group of two apples contains two common apples. That is, CRR in one group and CC in the other. Again, this is true for bowl 1 and bowl 2, so the probabilities are the same. (The order of apples doesn't matter within the groups because we will either eat all or none of the apples in a given group.) If we choose bowl 1, we eat the smaller group, and only die if that smaller group contains two common/poisonous apples. If we choose bowl 2, we eat the larger group and will only die if the smaller group (the one we didn't eat) contains two common/nonpoisonous apples (as this means that both of the poisonous apples were in the group we ate). So, without doing any math, you can see that the probabilities are equal, even if you can't tell what the probabilities are. This understanding of the problem also makes calculating the probability of death easier, if you want to calculate it. For one apple = death, you only survive if the small group has two rare apples. 2/5 * 1/4 = 1/10 (10% survival rate/90% survival rate) For two apples = death, you only die if the small group has two common apples. 3/5 * 2/4 = 3/10 (30% death rate/70% survival rate)
  23. You know the riddle: https://sites.math.washington.edu/~morrow/336_11/papers/yisong.pdf We have the exact same scenario & assumptions but with a different question to be answered: "Are you the last called prisoner out of the bunch?" In other words: "Are you the 100th prisoner?" Obviously, all prisoners called in the days 1-99 know they arent
  24. Event Horizon, you have shed a lot of light on this puzzle! Your observations about the 4-triangle and 1+ 3^n are quite surprising and pleasing. It is I who brute forced it; you actually came to a deeper understanding. I’ll send you kudos as well.
  25. Welcome here @ Silver. Note that the fool's mate requires 4 tosses
  1. Load more activity
  • Create New...