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DividedQuantum
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mathematical brain teaser thread
#21865684 - 06/27/15 07:15 PM (8 years, 7 months ago) |
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PLEASE SCROLL DOWN BEFORE POSTING AN ANSWER AS IT MAY ALREADY BE GIVEN. NEW PROBLEMS WILL BE ADDED AS WE GO.
I thought it would be fun to revisit some of Martin Gardner's mathematical games/brain teasers, and see who can be the first one to get the correct answers. (I don't know whether this is philosophical or not, but it didn't seem to fit anywhere else, either).
Please do not post a googled answer. Honor system.
Without further ado:
Quote:
Two girls were born on the same day in the same year to the same parents, yet they were not twins. Explain.
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Edited by DividedQuantum (06/27/15 08:08 PM)
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Weiliithinker
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They were born in different months!?
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deff
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wormholes 
i have no idea neat thread idea though !
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Khancious
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Re: mathematical brain teaser thread [Re: deff]
#21865815 - 06/27/15 07:38 PM (8 years, 7 months ago) |
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One of the girls had a mushroom instead of vagina
or
The parents were seminal-injected lesbians
-------------------- I am that, which is.
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once in a lifetime
sun child



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Re: mathematical brain teaser thread [Re: Khancious] 2
#21865938 - 06/27/15 08:00 PM (8 years, 7 months ago) |
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Triplets.
-------------------- Innocent, Oldfield & Hegerland Julia Delaney, Bothy Band Rasta Girl, Sister Carol Genesis, Jorma K I Wish You Peace, Lawrence Laughing Do Your Thing, Moondog large . . music garden . . veryall peace them hiStarhouse - main Time Traveler's Guide
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Khancious
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Re: mathematical brain teaser thread [Re: Khancious]
#21865950 - 06/27/15 08:03 PM (8 years, 7 months ago) |
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Or
The parents couldnt agree on a name, so they both saw their version of the child
Or
The girl is schizophrenic from all the mothers heroin abuse so there is an easily recognize personality disorder resulting in two identities and sets of memories pertaining to each
-------------------- I am that, which is.
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DividedQuantum
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Quote:
once in a lifetime said: Triplets.
  
Correct answer: They were in a set of triplets.
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DividedQuantum
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PROBLEM #2
Quote:
You want to construct a rigid wire skeleton of a one-inch cube by using twelve one-inch wire segments for the cube's twelve edges. These you intend to solder together at the cube's eight corners.
"Why not cut down the number of soldering points," a friend suggests, "by using one or more longer wires that you can bend at sharp right angles at various corners?"
Adopting your friend's suggestion, what is the smallest number of corners where soldering will be necessary to make the cube's skeleton rigid?
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deff
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i think you still need eight corners to solder as each corner is the joining of three sides, and three sides can never come from the same single piece ?
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DividedQuantum
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Re: mathematical brain teaser thread [Re: deff]
#21866037 - 06/27/15 08:22 PM (8 years, 7 months ago) |
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Quote:
deff said: i think you still need eight corners to solder as each corner is the joining of three sides, and three sides can never come from the same single piece ? 
  
Correct answer: The smallest number of soldering points remains eight no matter how wires are bent. Because an odd number of edges meet at each corner of a cube, every point requires soldering.
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DividedQuantum
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PROBLEM #3
Quote:
ABCD DCBA * * * * _____ 12300
ABCD are four consecutive digits in increasing order. DCBA are the same four in decreasing order. The four asterisks represent the same four digits in an unknown order. If the sum is 12,300, what number is represented by the four asterisks?
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deff
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4523
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DividedQuantum
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Re: mathematical brain teaser thread [Re: deff]
#21866102 - 06/27/15 08:34 PM (8 years, 7 months ago) |
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Quote:
deff said: 4523 
deff is two for two!   
Correct answer: If ABCD = 1,234, it is impossible to obtain a sum as large as 12,300. If ABCD = 3,456, it is impossible to obtain a sum as small as 12,300. Therefore ABCD = 2,345, from which it is easy to determine that the four dots stand for 4,523.
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DividedQuantum
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PROBLEM #4
Quote:
A variation of tic-tac-toe departs from the standard game in that each player, at each turn, may make either an O or an X. The first player to complete a row of three (either three Os or three Xs) wins the game.
Standard tic-tac-toe is a draw if both sides play rationally. This is not true of the unusual variant just described. Assuming that both players adopt their best strategy, who is sure to win: the first or second player?
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once in a lifetime
sun child



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The first player. Plays in the middle, then 2nd has to play an 'o',
if it's played on the side, first player does the same,
until this:
__________
| o | __________
o | x | o __________ | o | __________
when an x or an o in the corner allows victory.
if 2nd player plays an o in a corner, 1st player does the same,
whereupon this arises:
_________
| | o _________
| x | _________ o | | _________
and no matter what is played, is a win.
-------------------- Innocent, Oldfield & Hegerland Julia Delaney, Bothy Band Rasta Girl, Sister Carol Genesis, Jorma K I Wish You Peace, Lawrence Laughing Do Your Thing, Moondog large . . music garden . . veryall peace them hiStarhouse - main Time Traveler's Guide
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DividedQuantum
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Registered: 12/06/13
Posts: 9,819
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Quote:
once in a lifetime said: The first player. Plays in the middle, then 2nd has to play an 'o',
if it's played on the side, first player does the same,
until this:
__________
| o | __________
o | x | o __________ | o | __________
when an x or an o in the corner allows victory.
if 2nd player plays an o in a corner, 1st player does the same,
whereupon this arises:
_________
| | o _________
| x | _________ o | | _________
and no matter what is played, is a win.
  
That is the correct answer, and since your explanation (with illustrations) was so good, I'm not going to bother giving the official one.
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DividedQuantum
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PROBLEM 5
Quote:
Miranda beat Rosemary in a set of tennis, winning six games to Rosemary's three. Five games were won by the player who did not serve. Who served first?
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Khancious
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Rosemary
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DividedQuantum
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Re: mathematical brain teaser thread [Re: Khancious]
#21867903 - 06/28/15 10:22 AM (8 years, 7 months ago) |
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Without revealing whether this is in fact the correct answer or not, for this problem a one-word answer will not be accepted. Except in cases where a short-answer clearly solves the problem, please provide a detailed explanation of your reasoning.
Thank you.
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Sun King



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Who is rosemary?
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