The king and his two children are imprisoned at the top of a tall tower. Stone masons have been working on the tower and have left a pulley at the top. Over the pulley runs a rope with a basket attached at either end. In the basket on the ground is a stone like the ones use to build the tower. The stone weighs 75 lb. The king figures out that the stone can be used as a counterbalance, but if the difference in weight between the two baskets must greater than 15 lb they will not have the strength to operate the pulley. The King weighs 195 lb, the princess weighs 105 lb, and the prince weighs 90 lb.