Jump to content
BrainDen.com - Brain Teasers

All Activity

This stream auto-updates     

  1. Today
  2. Yesterday
  3. Shakeepuddn

    A Simple Riddle

    Nah. Generic deck.
  4. Thalia

    A Simple Riddle

  5. Thalia

    Ranks and Files : Dominoes

    I'm not quite sure what you are saying. A domino consists of 2 squares. So while there are 56 squares, there's only 28 dominoes. So for example, A2 and A3 together are a single domino. TSLF- Do you want them arranged in an 8x7 grid like the picture? That would mean some rows and columns would contain more than one of a number. Is that correct?
  6. rocdocmac

    Cutting pizza

    All cuts should be vertical and in any direction ... I only emphasized that no horizontal cut is allowed, e.g. one could possibly divide a cake with three cuts to yield 8 pieces ... 2 vertical cuts and 1 horizontal cut! (1) 125251 pieces after 500 cuts (correct) (2) 3162 cuts gives 500704 pieces (also correct) (3) Never mind the 3rd answer since I reckon that it must be infinity, although 199999 cuts as a first approximation comes very, very close! However, there will always be a remainder of either 1 or a pretty large number. Therefore, 2 remains the minimum and maximum pieces-to-cuts ratio. I cannot, though, prove this mathematically (yet)! I wasn't aware of an entry at "Mathworld"! So, my question should actually have been a straight-forward quickie!
  7. Shakeepuddn

    A Simple Riddle

    Well, it's outside the box, I'll give you that : )
  8. phil1882

    Cutting pizza

    i dont really understand the question. your picture seem contrary to your description. your picture seems to suggest you can cut in any direction, but your description suggests all cuts have to be in the same direction. i'll solve both. for lines in any direction: http://mathworld.wolfram.com/CircleDivisionbyLines.html 1/2*(n^2 +n +2), n=500; 125251 5000000 = 1/2*(n^2 +n +2) n=3162 for cuts in the same direction: each cut adds 1 new region. for 500 cuts, that 501 rejoins to get 5000000 peices 4999999 cuts are needed
  9. rocdocmac

    Cutting pizza

    Rather change "pizza" to an enormous 2D circle then! I used pizza as to eliminate any horizontal cut, but it will be a hell of a mess should one really had to cut a pizza into so many pieces!
  10. rocdocmac

    Ranks and Files : Dominoes

    Thank you Time-LSF! Good one, but ... Apology for raising this, but there is only one "double 0" and one "double 6" combination directly adjacent next to each other in the grid, although the total of 56 (7x8) matches twice the number of 28 domino pieces in a normal set! The "double 1, 2, 3, 4 and 5" are fine.
  11. plasmid

    A Simple Riddle

  12. Shakeepuddn

    A Simple Riddle

    Nope
  13. flamebirde

    A Simple Riddle

  14. TimeSpaceLightForce

    Cutting pizza

  15. TimeSpaceLightForce

    Ranks and Files : Dominoes

    A double six domino set. made up of 28 domino tiles.
  16. rocdocmac

    Ranks and Files : Dominoes

    Looks like a 7x8 set?
  17. TimeSpaceLightForce

    Ranks and Files : Dominoes

    Can you arrange the 6 x 6 domino set in order that all columns and rows contains 0 - 6 ?
  18. Shakeepuddn

    A Simple Riddle

    Nice try. Try again.
  19. Wilson

    A Simple Riddle

    I wouldn't bet the farm here Ace, but call.........
  20. Shakeepuddn

    A Simple Riddle

    Around my kind you may just find A curse, a laugh, a grin But pressure me, I'll likely snap And send away my friends. Up on deck or over it A simple one am I, But with a hand I take command Or from you I will fly.
  21. Last week
  22. rocdocmac

    Cutting pizza

    Suppose you have a pizza being cut vertically with one straight cut, you'll be left with two pieces. The ratio of number of pieces to cuts in such an instance will be 2 (a whole number, i.e. no remainder). If you cut a pizza using two straight vertical cuts, you'll have four pieces left (pieces-to-cut ratio = 2, also a whole number). Cutting the pizza thrice, the maximum pieces possible is seven (pieces/cuts = 7/3 = 2.3333..., i.e. there is a remainder of 1). See attached image. Questions ... (1) What is the maximum number of pieces that one would get by cutting the pizza 500 times using only straight vertical lines (no horizontal cuts allowed)? (2) How many cuts should one make to get a maximum of at least 5 million pieces? (3) The minimum piece-to-cut ratio with no remainder is exactly 2 as indicate above. What would be the next higher number of cuts, such that the number of resulting pieces divided by the number of cuts has no remainder?
  23. I do believe #3 -- What 3 positive numbers give the same result when multiplied and added together? -- is not grammatically correct. I believe the question should be -- What three positive numbers give the same result when multiplied together and when added together? The adverb should not be implying each operation occurs together, but should occur for each operation as each operation is intended to be independent, yet gives the same result. I do agree with Donald Cartmill that #12 also is not written as it should be.
  24. Wilson

    I'm not a bird

    I spy with my little eye something beggining with P......
  25. Donald Cartmill

    20 RIDDLES TO TEST YOUR MATH, IQ AND THINKING SKILLS.

    OK I disagree with our most sage and top contributor rocdocmac on 5, 8 , 12 is ok if you add 30 seconds ,17 ,20 . In addition I will be making corrections to #1 . What is the value of x If 1/2, 2/3, 3/4, 4/5, 5/6, 6/7, 7/8, 8/9, 9/10 then x/1000? x = 500,000 CORRECTION 2 = 999 2. If 4 and 2= 26, 8 and 1 = 79 and 6 and 5 = 111. Then, what is 7and3?...410 3. What 3 positive numbers give the same result when multiplied and added together? 2 mis interpreted the Q 1,2,3 is correct 4. What number do you get when you multiply all of the numbers on a telephone's number pad? zero 5. Here is a light switch. Note the order of the positions. If the light is now at medium and it is switched 3922 times what will be the position of the switch? medium I assumed in the absence of additional info there were 3 positions . i.e low , med , high. any even number of flips will put the sw back on med 6. Can you arrange four nines to make it equal to 100. 99 9/9 8. If 1/2 of 5 is 3, then what is 1/3 of 10? 3.67 This is NOT a math calculation I envisioned 1/2 of 5 = 2 1/2 + 1/2 = 3; therefore 1/3 of 10 = 3.33 + 1/3 =3.367 9. 100 students entered college. 55 of them chose music. 44 of them chose sports. 20 of them chose both. How many of them chose neither music nor sports? 21 Of the 55 ,20 choose both leaving 35 ; of the 44 ,20 choose both leaving 24; 35 music only ;24 sports only ; 20 M&S total=79 100 - 79 = 21 who do neither 10. Four friends are going to a concert. When they arrive, there are only five seats together left in the theater. The manager will let all four friends in for free if one of them can tell her how many different seating arrangements are possible for four people with five empty seats. 120 5 seats taken 4 at a time 5 ! All four are let in free. Could you have given the correct answer? 120 5 seats taken 4 at a time 5 ! 12. At six o’clock the wall clock struck 6 times. Checking with my watch, I noticed that the time between the first and last strokes was 30 seconds. How long will the clock take to strike 12 at midnight? 5 hrs 59 1/2 minutes NOTE: the question is not how long it chimes at 12 :00 ,but how long from the 30 seconds of chiming at 6:00 3. There are several books on a bookshelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf? 9 14. John has been hired to paint the numbers 1 through 100 on 100 apartments. my bad 20 How many times he has to paint 8? 20 15. You have two books. One of them is upside-down and the other is rotated so the top of the book is facing you. What is the sum of the first page in each book? 1 +1 Up side down ,laying on its side ,propped at an angle the first page is 1 16. There is a certain club which is for men only. There are 600 men who belong to this club and 5% of these men wear one earring. Of the other 95% membership, half wear two earrings and the other half wear none. How many earrings are being worn in this club? 600 17. Does a pound of gold or a pound of feathers weight more? feathers A pound of feathers weighs 16 ounces avoirdupois; Gold is weighed on the troy system whereby a troy pound is 12 oz ; 1 troy oz = 1.0971 oz avoirdupois therefore 1 pound of gold weighs 13.1652 oz avoirdupois 18. There is a chain nailed to the wall. The chain is 10 feet long and the center of the chain dips down 5 feet from where each side of the chain is nailed to the wall. How far are the 2 ends of chain from each other? on the same nail 19.Little Johnny is walking home. He has $300 he has to bring home to his mom. While he is walking a man stops him and gives him a chance to double his money. The man says "I'll give you $600 if you can roll 1 die and get a 4 or above, you can roll 2 dice and get a 5 or 6 on at least one of them, or you can roll 3 dice and get a 6 on at least on die. If you don't I get your $300." What does Johnny do to have the best chance of getting home with the money? keep on walking 20. If you have 6 women and 2 friends, how many women do each of your friends get if the friends are two of the 6 women;i.e. women themselves , then each is entitled to herself, or one each/ If the two friends are male then no women. Quote
  26. bonanova

    I'm not a bird

    Poe, E. Near a Raven Midnights so dreary, tired and weary. Silently pondering volumes extolling all by-now obsolete lore. During my rather long nap -- the weirdest tap! An ominous vibrating sound disturbing my chamber's antedoor. 'This,' I whispered quietly, 'I ignore.' - Mike Keith, 1995
  27. As problems #9 and #14, I admit to having made errors. Problem #12 is one of the problems that can have more than one correct answer. That is, there is more than one way of defining a stroke of a wall clock.
  28. Shakeepuddn

    I'm not an outlaw's ghost

    Ah . . . Good one. I was taking the "man" too literally.
  1. Load more activity
×