>>I may have already given this one, but what the heck, I'll give it again.
>>
>>There are 3 missionaries and 3 natives. They need to cross a river in a boat that only holds 2. The restraints are that the cannibals can't outnumber the Missionaries on either side because the missionaries feared that the natives would over-power and eat them.
>
>First two cannibals row over, then one cannibal rows the boat back. Then a cannibal and a missionary row over, and the missionary rows back. Then two missionaries row over, both stay and one of the cannibals rows back. Then the missionary and the cannibal row over, and the cannibal rows back. Then the two cannibals row over.

Actually, now that I think about it, depending on how it is counted, that may or may not be the answer, ie if it counts as the person being on the other side, this solution is false, but another works. But if it doesn't count until the person leaves the boat, this would work. So what exactly does count as the person being on the other side? Leaving the boat or just rowing over?