Surplus of consumers are considered as the significant in the cost-benefit to analysis on the public investment for the welfare of the society. Rate of the product is always less than what a person is willing to pay for it. The difference between consumers wills to pay and those actual pays lead to satisfaction which is consumer surplus.On the other hand, surplus of producer exists when actual price exceeds the minimum price that the seller is ready to accept. Resource owners usually captured producer’s surplus.Meaning of Consumer Surplus:At first, Marshall had proposed the theory of consumer surplus which is based on demand theory....