(Hopefully this one hasn't been posted it's a really old one I think don't post a solution if you ALREADY know the answer I haven't posted the solution cause I want people to actually try and not just look at the question then giveup right away.)

An old man has a boat and needs to cross the river, the problem is he has three things he needs to get across the river a chicken, a dog, and a sack of grain. He has three problems:

His boat can only support himself and one item,

The dog can't be left with the chicken, and

The chicken can't be left with the grain.

How does he get across with all three items intact?

DG | --C--> |
DG | <--  -- | C
D   | --G--> | C
D   | <--C-- | G
C   | --D--> | G
C   | <-- --  | DG
     | --C--> | DG

The trick is that the Dog and Grain are cool together.

Posted by owl on 2005-08-18 19:51:46