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Brainteaser III
Posted: Sun Mar 31, 2002 2:56 pm
by frogus
Two men, call them A and B, get together with their friend C. C tells them both to chose a positive whole number and whisper it secretly into his ear. They do this, and C says 'Neither of you will be able to tell who has chosen the larger number'. A chose 157. Was C's prediction correct?
Posted: Sun Mar 31, 2002 7:39 pm
by Aragorn Returns
i don't get it, 157 isn't even positive.
Posted: Sun Mar 31, 2002 9:03 pm
by Aegis
Originally posted by frogus
Two men, call them A and B, get together with their friend C. C tells them both to chose a positive whole number and whisper it secretly into his ear. They do this, and C says 'Neither of you will be able to tell who has chosen the larger number'. A chose 157. Was C's prediction correct?
It is correct, because C will have to tell them.
Posted: Sun Mar 31, 2002 9:12 pm
by Aragorn Returns
sorry about my last post here, had a little brain fart, lay off the marijuana kids.
Posted: Mon Apr 01, 2002 5:10 am
by frogus
@Aegis..think about this...
If B had chosen 1, he would know that A had a larger number...So B cannot have 1. Now by the same logic, B can deduce that A doesn't have 1 either. Now knowing that neither of them have 1, A can go on to deduce that B doesn't have 2 either, because he knows that B is a perfect logician and will have made the same figurings out as him. This can go on until A gets to 157, deducing by mathmatical abduction that B cannot have a number less than 157...so B must have the biggest number, right?
Posted: Mon Apr 01, 2002 5:37 am
by Un-Maimed
of course C is correct - he knows both numbers and therefore knows A & B both (happened) to say 157, then neither have the bigger number
nuf said!
Posted: Mon Apr 01, 2002 5:51 am
by frogus
ahh...sorry I didn't make this clear...I didn't mean this as a real life situation, just an exercise in logic and mathematics...Bs number is just a variable...
Posted: Mon Apr 01, 2002 6:25 am
by Un-Maimed
Just guessing at this - the statement 'Neither of you will be able to tell who has chosen the larger number' is correct because a) the parties A & B dont have enough info to KNOW the others number. As an aside - guess doesnt count as "knowing who has the highest number" cum on - tell me if im in the right ball park
!! puhleeese!
Posted: Mon Apr 01, 2002 10:27 am
by Aegis
I still say C...
Posted: Mon Apr 01, 2002 4:50 pm
by frogus
@ Un-M..read the 'Aegis...think about this' post. Doesn't it prove that B must have the biggest number?
maybe I'll give you a clue in a minute, cos you're not really getting to the real logic of the matter...anyway, could be noone's interested in my puzzles anyway...*sob*...