Kara is shopping for apples at the farmers' Market. She visit three different fruit stands that have different specials for their apples. Keller's Fruit is selling 5 pounds for $6.25. Prum's Fruit is selling 3 pounds for $3.90, Apples is selling 6 pounds for $7.20. Find each price per pound. Which stand is offering the lowest price per pound apples?