EPTPuzzleing Question! (HARD) - Page 61
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Catyoul
France2377 Posts
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Jim
Sweden1965 Posts
 The guy with 50 apples buys all his brothers apples. The middle brother also buys 20 of the oldest brother's apples. This leaves everybody with 10 apples worth of money. | ||
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MoltkeWarding
5195 Posts
On November 25 2004 08:18 BigBalls wrote: Ok, im about ready to leave for thanksgiving, so ive decided i should post a few problems for when im gone. Have fun with these guys, theyre tricky... Three youngsters each have some apples to sell. The oldest has 10, the next had 30, the youngest had 50. How is it possible for each to sell his apples at the same price yet receive the same amount of money? There are many solutions to this, but each is difficult to come up with. Didnt want to type this one out....but oh well Aunt jenny has 3 greedy nephewss, Phil, Sam and George, who were looking forward to her death so they could split her will. Jenny dies, but she decided to play a trick on them and made out her will as follows. The total estate amounts to 1,717 and is to be shared as follows: Philip gets 1/2 Sam 1/3 George 1/9 Each is to receive an amount in even dollars only The boys have no clue how to split the money, and go to the lawyer who then figures out the problem and splits their money. How does he do it? edit: messed up, george gets 1/9 NOT 1/6 For question 1: They have different numbers of apples, but sell the same number of apples each | ||
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MoltkeWarding
5195 Posts
On November 25 2004 20:13 Catyoul wrote: Oh sorry, the '5 am effect', it's 9/17, 6/17 and 2/17 of course :p If philip receives 9/17, he'll be receiving more than 1/2. While the ratios would be correct, the amount would be wrong. There is 1/18 unaccounted for in this riddle. The riddle also states: the assets total 1717 BEFORE they go to the lawyer, so we cannot deduce that it was originally over 1717. | ||
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BigBalls
United States5354 Posts
and no jim, that wasnt the answer, its actually fucked up and retarded now that i realize it, so ill just post it. Basically, the key observation to make is that 10 = 3 mod 7 30 = 2 mod 7 50 = 1 mod 7 furthermore 10 = 1*7+3 30 = 4*7+2 50 = 7*7+1 write each as an ordered pair (1,3)(4,2)(7,1) its easy to see that this is linear and that 3x = y. So basically x here is a group of 7, y is a group of 1, so we sell groups of 7 for 1 dollar each and leftover ones for 3 dollars each. yeah, makes no sense at all, but hey, its a cool solution | ||
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Jim
Sweden1965 Posts
edit: the solution is quite beautiful if you are leaning towards the nerdy side. | ||
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KarlSberg~
731 Posts
It reminds me of a guy I saw selling cakes for 5F, drink for 4F and drink+cake for 10F | ||
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baal
10541 Posts
On November 25 2004 11:16 GroT wrote: hmmm actually i take back what I said, i'm talking to a friend who i trust and he says that you are right baal Trust me i can be an ass, but im way over these bunch of 15y/o dumbasses who havent even taken 1 advanced course of probabilities, they dont seem to realize that probability is chained to events and cannot be analized as their logic tells them as isolated events. Its frustrating because i see it as if some kid is telling me 2+2 is 22, and insists to no end thats logical, im sorry if their ignorance pisses me off, but well... it does. | ||
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BigBalls
United States5354 Posts
catyoul is working on his phd karlsberg graduated with a degree in math im a 3rd year college student, but i finished my math major long ago, now working on graduate level courses all of us AND BASICALLY EVERYONE ELSE are saying you are wrong and we are right. You have not even addressed any of our posts, in which all of us clearly state the differences in the wordings. Consider the following problems: the first 9 children are girls, what is the probability the 10th is a boy? 1/2 there are at least 9 girls, what is the probability the 10th child is a boy? 1/11. there are at least 9 girls, what is the probability there is a boy? 10/11. THAT is the difference. | ||
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baal
10541 Posts
What is more likely to happen in 10 coin tosses: 10 consecutive tails, or 9 tails and 1 head? Answer me that and ill elaborate. | ||
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BigBalls
United States5354 Posts
On November 25 2004 17:05 Catyoul wrote: While discussing this by PM, I think I came up with the ultimate counter-argument against the 2/3 people. Ok, so let's imagine you guys are right. So that means that I go to the door, a girl opens me, it means that the other child has 2/3 chance of being a boy. Using the same line of thought, if a boy opens me, it means that the other child has 2/3 chance of being a girl. The argument for that being the following : 4 different cases : GG GB BG BB All have the same 1/4 probability. When a girl comes at the door, it means you have eliminated BB, thus 3 cases left, yadda yadda. At the same time, you will agree that there is on average a 50% chance that a boy or girl answers the door in all 2 children houses right ? (until now, it's all pretty obvious, no magic yet). Now, you have this : - chance that a girl opens : 1/2 - chance that a boy opens : 1/2 - if a girl opens : chance of a boy being 2nd : 2/3 thus : if a girl opens, chance of a girl being 2nd : 1/3 - if a boy opens : chance of a girl being 2nd : 2/3 thus : if a boy opens, chance of a boy being 2nd : 1/3 Total chances : GG : girl + girl = 1/2 * 1/3 = 1/6 GB : girl + boy = 1/2 * 2/3 = 1/3 BG boy + girl = 1/2 * 2/3 = 1/3 BB : boy + boy = 1/2 * 1/3 = 1/6 That is a direct consequence of the 2/3 and in total contradiction with the fact these 4 cases have an equal probability of 1/4. Damn, I should have kept count of the number of counter-arguments I came up with on that problem :p refer to this beautiful post on why 2/3 is wrong. if you dont understand a simple contradiction argument, well then i cant even argue maths with you | ||
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baal
10541 Posts
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BigBalls
United States5354 Posts
and yes, i know there is 1/1024 chance of getting 10 tails out of 10 and 10/1024 chance of getting 9 tails out of 10. | ||
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Jim
Sweden1965 Posts
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BigBalls
United States5354 Posts
the first 9 children are girls, what is the probability the 10th is a boy? 1/2 there are at least 9 girls, what is the probability the 10th child is a boy? 1/11. there are at least 9 girls, what is the probability there is a boy? 10/11. | ||
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Jim
Sweden1965 Posts
On November 25 2004 21:33 BigBalls wrote: baal.........did you even read my post.......... and yes, i know there is 1/1024 chance of getting 10 tails out of 10 and 10/1024 chance of getting 9 tails out of 10. got to know the difference between ordered choice and not! | ||
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MoltkeWarding
5195 Posts
On November 25 2004 21:33 BigBalls wrote: ill put it in bold for you cause you seemed to have missed it the first 9 children are girls, what is the probability the 10th is a boy? 1/2 there are at least 9 girls, what is the probability the 10th child is a boy? 1/11. there are at least 9 girls, what is the probability there is a boy? 10/11. Not just first 9 children. If any 9 children are girls, the probability for 10th is a boy is still 1/2. :S | ||
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baal
10541 Posts
Anyway about the "if a girl opens the door" problem, ill put it in a simple way for u simple minded people. Think global, the world population is near to 50% male 50% female... If a girl opens the door and STILL theres a 50% that the other people in the house is a girl, that means that globally there would be a 75% of female population. If you dont get this after that explanation my friend, you should quit college and become a bum :D BTW catyoul its a shame that you are on a phd lvl with such an skill >.<, guess hard work compensates raw brains. | ||
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BigBalls
United States5354 Posts
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Jim
Sweden1965 Posts
Ps. I dont understand why you insult catyoul. He makes very intelligent posts and generally is very descriptive and helpful. | ||
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