Yolanda runs a bullfrog farm and when she employed one person, she produced 1,000 bullfrogs a week. When she hired a second worker, her total product doubled. Her total product doubled again when she hired a third worker. When she hired a fourth worker, her total product increased but by only 1,000 bullfrogs. Yolanda pays $1,000 a week for equipment and $500 a week to each worker she hires.