Weigh one of the first, two of the second, three of the third etc... If the weight is off by one hundredth of an ounce then it is the first set, if the weight is off by two hundred of an ounce then it is the second set, etc...
2) Not Available
3) 1 Gold Coin
The most senior pirate could give the coin to the least senior pirate. He can use the same logic in the previous puzzle to explain the futility of anyone trying to keep the coin for himself.
4) The Boxes
Pick from the one labeled "Apples & Oranges". This box must contain either only apples or only oranges.
E.g. if you find an Orange, label the box Orange, then change the Oranges box to Apples, and the Apples box to "Apples & Oranges"
