Question

Difficulty: EasyConcept and Calculation of Consumer Surplus

A consumer's maximum willingness to pay for four successive bags of rice is ₦15,000, ₦13,000, ₦11,000, and ₦9,000 respectively. If the prevailing market price per bag is ₦9,000, what is the total consumer surplus derived in Naira?

Answer: 12000

Answer

The total consumer surplus derived by the consumer is ₦12,000.
Consumer surplus is the difference between total willingness to pay and total actual expenditure. The total willingness to pay for the 4 bags of rice is ₦15,000 + ₦13,000 + ₦11,000 + ₦9,000 = ₦48,000. Since each bag costs ₦9,000, total expenditure for 4 bags is 4 × ₦9,000 = ₦36,000. Subtracting ₦36,000 from ₦48,000 gives a consumer surplus of ₦12,000.

Step-by-Step Solution

1
Sum the maximum willingness to pay for all consumed units to find Total Willingness to Pay.
Total Willingness to Pay = ₦15,000 + ₦13,000 + ₦11,000 + ₦9,000 = ₦48,000.
Total utility or willingness to pay is the cumulative value derived from consuming all 4 units.
2
Multiply the number of purchased units by the market price per unit to calculate Total Actual Expenditure.
Total Expenditure = 4 × ₦9,000 = ₦36,000.
The market price applies uniformly to all units purchased.
3
Subtract Total Expenditure from Total Willingness to Pay to calculate Consumer Surplus.
Consumer Surplus = ₦48,000 - ₦36,000 = ₦12,000.
Consumer surplus is defined as the net benefit (Total Willingness to Pay minus Total Expenditure).

Key Concept

Concept and Calculation of Consumer Surplus

Alternative Method

Alternatively, calculate the individual surplus for each unit (Willingness to Pay - Market Price) and sum them up: 1st unit (₦15,000 - ₦9,000 = ₦6,000), 2nd unit (₦13,000 - ₦9,000 = ₦4,000), 3rd unit (₦11,000 - ₦9,000 = ₦2,000), 4th unit (₦9,000 - ₦9,000 = ₦0). Total Consumer Surplus = ₦6,000 + ₦4,000 + ₦2,000 + ₦0 = ₦12,000.
Estimated Time:1m 0s
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