Jump to content
BrainDen.com - Brain Teasers

All Activity

This stream auto-updates     

  1. Today
  2. 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.
  3. Yesterday
  4. 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?
  5. 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.
  6. Wilson

    I'm not a bird

    I spy with my little eye something beggining with P......
  7. 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
  8. Last week
  9. 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
  10. 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.
  11. Shakeepuddn

    I'm not an outlaw's ghost

    Ah . . . Good one. I was taking the "man" too literally.
  12. plasmid

    I'm not an outlaw's ghost

    Right on! I wrote this riddle just after seeing essentially this
  13. plainglazed

    I'm not an outlaw's ghost

    then how about a
  14. plasmid

    Bowling for equilateral triangles

    I had to think about it a bit to convince myself that the statement at the end of the first paragraph is really true, but I believe it is. For anyone not seeing it easily:
  15. Donald Cartmill

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

    . 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 x =900 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 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.
  16. plasmid

    I'm not an outlaw's ghost

    You're getting quite close, plainglazed.
  17. plainglazed

    I'm not an outlaw's ghost

    okay, time to purge - been thinking along the lines of but still thinking am not quite there. much fun plasmid!
  18. plasmid

    I'm not an outlaw's ghost

    Getting warm, but still looking for something that's hidden while out in the open.
  19. rocdocmac

    Square Free

    So ... 3x best answers from me?
  20. Shakeepuddn

    I'm not an outlaw's ghost

    I'll say:
  21. Wilson

    I'm not an outlaw's ghost

    Hole In The Wall Gang....
  22. Donald Cartmill

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

    . 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 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 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 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 13. 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 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 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.
  23. Donald Cartmill

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

    . 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 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 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 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 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 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. 240 All four are let in free. Could you have given the correct answer? 240 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 13. 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. 11 How many times he has to paint 8? 11 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 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 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.
  24. plasmid

    I'm not an outlaw's ghost

    I'm not a picture frame. Tough in my mind to interpret it as having been found only by those now dead. Also not a skydiver. I'm something more commonly known for grabbing everything. Not an excavator. I don't envision him hanging and then being hung by the same "man". And also not a shovel for similar reasoning.
  25. Shakeepuddn

    I'm not an outlaw's ghost

    Sorry, no spoiler with phone. I go shovel.
  1. Load more activity
×