Potatoes cost janice $1 per pound, and she has $5 that she could possibly spend on potatoes or other items. if she feels that the first pound of potatoes in 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 will she purchase

The first three pounds of potatoes have the following cost.
 (1.50) + (1.14) + (1.05) = 3.69 $
 Therefore Janice will have the rest to continue buying
 5-3.69 = 1.31 $
 Since the rest of the pounds are worth $ 0.30 per pound, she will be able to buy the next additional amount
 (1.31) / (0.30) = 4.36
 That is, you can buy an additional 4 pounds.
 answer
 She will purchase 7 pounds of potatoes.