Michael places a ladder of mass 17 kg against his house. The feet of the ladder are resting on his concrete patio at a distance of 0.71 m from the house. Between the ladder and the concrete, μs=0.42. The top of the ladder rests against a plastic rain gutter. The friction between the laddder and gutter is negligible. The top of the ladder is at a height of 1.14m above the concrete patio. The ladder's center of gravity is at its midpoint. Michael is standing on a rung at a horizontal distance of 0.21m from the house. What is the maximum mass that Michael could have without causing the ladder to slip on the concrete?