James recorded his reading times over the course of 5 days. He would like to figure out his reading rate. Find the slope of his data. time(min) :
4,8,12,16,20

- Numbers of pages read:
5,10,15,20,25

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.