Three people picked 68 apples together. At the first tree they each picked the same number of apples. At the second tree they picked 3 times as many as they picked at the first tree. When they finished at the third tree, the group had 5 times as many apples as they had when they started at that tree. At the fourth tree the group picked just 8 apples. How many apples did each person pick at the first tree?