Mrs. thomas has $71.00 to purchase bottles of juice for her class. if the bottles of juice cost $3.55 each, how many bottles can she buy

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.