An employee makes an hourly rate plus any tips they earn. this tip employee made a total of $400 by working 28 hours last week. if $253 of their total earnings was their tips, what is their hourly rate of pay?

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.