3 Negative Marginal Revenue. The manager of your firm is puzzled because the larger the quantity of output sold, the lower its total revenue. The manager gets weekly data in a table with two columns...

3 Negative Marginal Revenue. The manager of your firm is puzzled because the larger the quantity of output sold, the lower its total revenue. The manager gets weekly data in a table with two columns of numbers: Quantity Sold and Total Revenue. After you do some computations and add a third and a fourth column of numbers, the manager looks at the new table and says, “Aha, now I see why selling more decreases total revenue.”

a. The third column of numbers has data on
, and the fourth column has data on
.

b. How do the additional columns of numbers explain the negative relationship between quantity sold and total revenue?