Kim hires students to paint houses at $400 a week and leases business equipment that costs $300 a week. The table shows Kim's total product and total cost schedules. Total Total product cost Labor (houses (dollars (students) per week) per week) 300 700 SOUND 1.100 OUT A W N - O 1,500 1.900 18 2,300 21 2,700 At what output is Kim's average total cost at a minimum?Kim's average total cost is at a minimum when she paints Type houses a week