The table shows the marginal value (MV) schedule for person A. The marginal values are measured in dollars. Assume that the buyer will buy if the price is smaller and equals the MV. Enter your answers in numerals.

Quantity of X	MV
1	20
2	18
3	16
4	14
5	12
6	10
7	8
8	6
9	4
10	2
11	0

The highest price (per unit of X) at which Person A would buy 2 units of X is per unit of X.

The highest price (per unit of X) at which Person A would buy 3 units of X is . If the price of X for every single item fell from 18 to 16, the law of demand tells us that Person A will purchase more units of X. What is the change in A's total expenditure from increasing the quantity of X he purchases? NOTE: Only enter a numeral in your answer, without a + or - sign. .

If the price of X for every single item fell from 12 to 10, what is the change in A's total expenditure from increasing the quantity of X he purchases? NOTE: You may need to enter a + or - followed by a numeral in your answer, unless the answer is 0. .

If the price of X for every single item fell from 4 to 2, what is the change in A's total expenditure from increasing the quantity of X he purchases? NOTE: Only enter a numeral in your answer, without a + or - sign. .