Oranges cost Chris $2 per pound, and she has $10.00 that she could possibly spend on oranges or other items. If she feels that the first pound of oranges is worth $2.50, the second pound is worth $2.25, the third pound is worth $1.50, and all subsequent pounds are worth $1.00, how many pounds of oranges will she purchase? What if she only had $4 to spend?

Chris will keep on purchasing oranges as long as they are worth more to Chris than the price she pays for them. The price of each pound of oranges is $2. The first pound is worth $2.50 to Chris. Because $2.50 > $2, she will buy the first pound.

Similarly, the second pound is worth $2.25 to her. Again, $2.25 > $2, so she will buy the second pound as well. But the third pound is worth $1.50 only to Chris. Because $1.50 < $2, she will not buy the third pound. Also, each subsequent pound is worth even less ($1), so she will not buy any more pounds of oranges.

Therefore, Chris will purchase 2 pounds of oranges only, at $2 per pound. This means she will spend $4 on oranges, and the remaining $6 that she has on other items.

If Chris had only $4 to spend, she would again end up buying the 2 pounds of oranges as the worth of these oranges in her sight has not changed. Therefore, in this case, she would spend the entire $4 amount on oranges.