Brainteaser III

frogus · Post by **frogus** » Sun Mar 31, 2002 2:56 pm

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?

Aragorn Returns · Post by **Aragorn Returns** » Sun Mar 31, 2002 7:39 pm

i don't get it, 157 isn't even positive.

Aegis · Post by **Aegis** » Sun Mar 31, 2002 9:03 pm

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.

Aragorn Returns · Post by **Aragorn Returns** » Sun Mar 31, 2002 9:12 pm

sorry about my last post here, had a little brain fart, lay off the marijuana kids.

frogus · Post by **frogus** » Mon Apr 01, 2002 5:10 am

@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?

Un-Maimed · Post by **Un-Maimed** » Mon Apr 01, 2002 5:37 am

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!

frogus · Post by **frogus** » Mon Apr 01, 2002 5:51 am

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...

Un-Maimed · Post by **Un-Maimed** » Mon Apr 01, 2002 6:25 am

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!

Aegis · Post by **Aegis** » Mon Apr 01, 2002 10:27 am

I still say C...

frogus · Post by **frogus** » Mon Apr 01, 2002 4:50 pm

@ 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*...