Brain Teasers and Maths Puzzles

[eMTe]

Certainly he does being blind and subjected to devious schemes of omnipotent mathematician. But he has no choice.

[eMTe]

I still wait for Tormuse, who always participated actively in this topic. Because, much to my regret, nobody seems to know the answer. Or at least nobody tried to find it.

Hint: puzzle is not lateral.

[Pater Alf]

Is the man allowed to ask questions? And does he need to use all cards?

[eMTe]

Is the man allowed to ask questions?

No, he is not allowed. He's a slave. If his answer is wrong he is forced to have a reverse gangbang intercourse with forty Japanese teenagers, so he desperately tries to answer correctly.

And does he need to use all cards?

Sure he does, otherwise he would end up with more than TWO piles.

[Zyx]

Is the man allowed to ask questions?

No, he is not allowed. He's a slave. If his answer is wrong he is forced to have a reverse gangbang intercourse with forty Japanese teenagers, so he desperately tries to answer correctly.

Female or male teenagers?

[eMTe]

It wasn't disclosed in original puzzle, so I believe this information is not crucial for the solution.

[Pater Alf]

Even if I have no idea how this should lead to a solution: Is he allowed to turn cards around?

[eMTe]

Whatever. Why not?

[Drasir-Vel]

Blind man is given a standard pack of cards (52). Ten of these cards are with faces up.

Now his task is to make two piles (they can contain different number of cards), but each pile must contain the same number of cards with faces up.

What does he do?

Hint: the man is blind, but the cruel puzzle creator didn't allow him to use cards with braille

He asks someone else to do it for him?

[eMTe]

That would mean the puzzle is lateral, but it isn't. It is logical and mathematical.

[Pater Alf]

I even picked up a deck of cards and tried some things. But I still have no idea how it can be done.

[eMTe]

Since I know the solution I know it can be done. I tried to prove that there's a hole, but there isn't.

[Tormuse]

I still wait for Tormuse, who always participated actively in this topic. Because, much to my regret, nobody seems to know the answer. Or at least nobody tried to find it.

Aww, I didn't realize you were waiting for me!

Is the man allowed to ask questions?

No, he is not allowed. He's a slave. If his answer is wrong he is forced to have a reverse gangbang intercourse with forty Japanese teenagers, so he desperately tries to answer correctly.

Female or male teenagers?

Female... but he's gay, so he doesn't like it.

Even if I have no idea how this should lead to a solution: Is he allowed to turn cards around?

I have a feeling this is part of the solution, but the trouble is that if he can't tell which way the cards are to start, he could just as easily turn the face-up cards down as turn the face-down cards up, and any card he separates from the deck could go either way without his knowing which way it is. I'll have to give this some thought, but I don't see how to do this right away unless he has some extra source of information.

Just to clarify, there's no way for him to tell which way a card is turned using his other senses?

[eMTe]

I can clarify it once again - this puzzle is pure maths and logic, so no other senses are involved and no laterality at all.

[Tormuse]

I've got it! All ten face-up cards leave the island on the tenth day after the Guru announces she sees a blue-eyed card!

(Just kidding)

I've been thinking about this puzzle a fair bit today, considering different ways of dividing the deck and flipping portions of it, and remixing them, but it all comes out the same... There's no way for the blind man to know which way any given card starts or finishes, or what proportion of any section of the deck has cards that are face-up at any given time. I'm sorry; I don't see how to solve this. I think I need a hint. (Just a hint!)

[Pater Alf]

Same here. I tried a lot of things with a deck of cards to find a solution. But I can't see that there is a way to solve this puzzle. So a hint would be great.

[eMTe]

There's no way for the blind man to know (...) what proportion of any section of the deck has cards that are face-up at any given time.

And here you are wrong!

[Tormuse]

Was that the clue?

Sorry, eMTe, I don't see it. At the start, there are 10 face-up cards and 42 face-down cards. You can flip the whole deck to have 10 face-down cards and 42 face-up cards, but it doesn't make any difference. If you flip any one card, you will either be turning a face-up card down, or a face-down card up without knowing which you are doing. If you divide the deck into sections, you won't know how many in each section are face-up or how many are face-down, so if you flip that section, you won't know how many of each you're reversing.

I'm sure there's a very interesting solution to this, but I think I need a bigger hint than simply being told that I'm wrong.

[eMTe]

What's funny is that you have discovered the solution, but you don't believe that this is the solution. So as a hint - please read your last post once again.

[Pater Alf]

The more I try and the more I think about it, the less I believe there really is a solution. You can flip around cards and devide the deck into sections as long as you want. If you don't know where the face-up cards in the beginning, it won't help you.