Solutions :
-Wolf Sheep & Cabbage
Bring the sheep first, go back, take the cabbage (or the wolf), come back with the sheep and bring the wolf (or the cabbage).
-Cannibals & Missioneries
First, bring one man and one cannibal, the man comes back alone.
Then, bring two cannibals, one goes back alone.
Bring two men, one goes back with a cannibal.
Bring the last two men, one cannibal goes back.
Finaly, bring the cannibals (two times).
