Twenty-four 4-inch wide square posts are evenly spaced with 5 feet between adjacent posts to enclose a square field. what is the outer perimeter, in feet, of the fence? express your answer as a mixed number.

Use stokes' theorem to evaluate c f · dr where c is oriented counterclockwise as viewed from above. f(x, y, z) = xyi + 5zj + 7yk, c is the curve of intersection of the plane x + z = 8 and the cylinder x2 + y2 = 81.