#### Posers and Puzzles

- Joined
- 08 Dec '06
- Moves
- 23604

My friend sent me this:

"There are 42 coins on a table. Of those, 10 are heads-up and the other 32 are tails-up.

How can you separate the coins into two groups so that each contains the same number of coins that are heads-up?

Note that you cannot see nor feel the coins, though you can manipulate them. (you are blindfolded and wearing gloves)."

I solved it and proved that my solution is correct. I'm interested in seeing if other solutions exist.

127.0.0.1

- Joined
- 18 Dec '03
- Moves
- 16107

@damionhonegan *said*

My friend sent me this:

"There are 42 coins on a table. Of those, 10 are heads-up and the other 32 are tails-up.

How can you separate the coins into two groups so that each contains the same number of coins that are heads-up?

Note that you cannot see nor feel the coins, though you can manipulate them. (you are blindfolded and wearing gloves)."

I solved it and proved that my solution is correct. I'm interested in seeing if other solutions exist.

Reveal Hidden ContentTake 10 coins from the pile of 42 and move them into a separate pile. Flip all 10 of those over.

Reveal Hidden ContentIf you happen to pick all 10 of the heads-up coins, both piles have 0. If you pick n of the head-up coins, both piles will have 10-n

- Joined
- 08 Dec '06
- Moves
- 23604

@forkedknight

This is my solution. Are there any other?

- Joined
- 26 Apr '03
- Moves
- 26099

@damionhonegan *said*

This is my solution. Are there any other?

Put 32 coins into a new pile and flip the ten coins left in the other pile.

tinyurl.com/y43jqfyd

- Joined
- 23 Aug '04
- Moves
- 24791

Put all the coins on the edge.