What is the average (arithmetic mean) height of the n people in a certain group?
(1) The average height of the \frac{n}{3} tallest people n the group is 6 feet 2\over{\frac{1}{2}} inches, and the average height of the rest of the people n the group is 5 feet 10 inches.
(2) The sum of the heights of the n people is 178 feet 9 inches.