Janice really likes potatoes. Potatoes cost $1.00 per pound, and she has $6.00 that she could possibly spend on potatoes or other items. Suppose she feels that the first pound of potatoes is worth $1.50, the second pound is worth $1.14, the third pound is worth $1.05, and all subsequent pounds are worth $0.30. how many pounds of potatoes will she purchase?