Final answer:
The student's question appears to be about calculating the marginal revenue of a private seller given a demand function. However, the term 'deficit figure for the marginal revenue' is not standard and needs clarification. Without more context or additional information such as a supply function, providing an accurate deficit figure for marginal revenue is not possible.
Step-by-step explanation:
The student's question concerns the calculation of marginal revenue for a private seller given a demand function. The demand function provided is P = 1.4Q + 87, where P is the price and Q is the quantity demanded. To find the marginal revenue, we typically differentiate the total revenue function with respect to quantity, Q. However, the demand function needs to be converted to a total revenue (TR) function, which is P multiplied by Q (TR = P*Q). From the demand curve, TR = (1.4Q + 87)*Q. The derivative of TR with respect to Q gives us the marginal revenue (MR). However, the student has asked for a 'deficit figure for the marginal revenue,' which is unclear as 'deficit' typically refers to a shortfall or loss. Without additional context, calculating a deficit figure for marginal revenue is not standard economics terminology.
Using graphs, which was suggested as an alternative for solving models, we see that the quantity where supply equals demand (Qs = Qd) and where the demand curve intersects the supply curve determines the equilibrium price and quantity. If we know the supply function, we can graph both demand and supply to find this point of intersection. However, without the supply function, we cannot find the equilibrium or calculate the producer surplus, which represents the extra benefit producers receive when they sell at a market price higher than the minimum they would accept.