Lập bản kế hoạch ra mắt sản phẩm

Which of the following statements accurately describes how costs and benefits are calculated?

mark, a civil engineer, entered into a contract with david. as per the contract, mark agreed to design and build a house for david for a specified fee. mark provided david with an estimation of the total cost and the contract was mutually agreed upon. however, during construction, when mark increased the price due to a miscalculation on his part, david refused to pay the amount. this scenario is an example of a mistake.

Richardson hired j.c. flood company, a plumbing contractor, to correct a stoppage in the sewer line of her house. the plumbing company's 'snake' device, used to clear the line leading to the main sewer, became caught in the underground line. to release it, the company excavated a portion of the sewer line in richardson's backyard. in the process, the company discovered numerous leaks in a rusty, defective water pipe that ran parallel with the sewer line. to meet public regulations, the water pipe, of a type no longer approved for such service, had to be replaced either then or later, when the yard would have to be excavated again. the plumbing company proceeded to repair the water pipe. though richardson inspected the company's work daily and did not express any objection to the extra work involved in replacing the water pipe, she refused to pay any part of the total bill after the company completed the entire operation. j.c. flood company then sued richardson for the costs of labor and material it had furnished. (c) for what, if anything, should richardson be liable? explain."