Gallant Carpet Cleaning cannot meet demand with its current equipment. Gal- lant Carpet Cleaning is considering two new carpet cleaning machines. Machine A cleans carpets to residential standards, while machine B cleans and sanitizes carpets to hospital standards. Machine A costs $20,000 and machine B costs $50,000. The company estimates its cost per cleaning (including all chemicals) for machine A will be $8 and machine B will be $7. The revenue per carpet cleaned for A would be $40, while B could bring in $45 per carpet, due to the higher degree of sanitation pro- vided. Machine B needs to clean how many more carpets than machine A to break even?