Carly sharpens knives in her spare time for extra income. Buyers of her service are willing to pay $2.95 per knife for as many knives as - Carly is willing to sharpen. On a particular day, she is willing to sharpen the first knife for $2.00, the second knife for $2.25, the third knife for $2.75, and the fourth knife for $3.50. Assume Carly is rational in deciding how many knives to sharpen. Her producer surplus is