PLZ HELP! Oliver is 8 feet above the surface of the water. There is a school of fish 10 feet below the surface. A ledge with some seashells is 18 feet below the​ surface, and even​ deeper, there is a shipwreck 32 feet below the surface. Answer parts a and b.
a. How many feet will Oliver have to travel to get to the​ seashells?
Oliver will have to travel ? feet down