Suppose that 4 hours of socially necessary labour time are embodied in the commodities that typical workers and their families must consume each day. Then half the labour of an 8-hour workday forms that value of a day's labour power. Assume that 8 hours of labour time are required to produce the 2 ounces of gold coins. During the half of a workday, each laborer works with a machine and converts 10 pounds of cotton in weight into 10 pounds of cloth. The cotton and the machine used up during the 4 hours of labour has a value of 16 hours of labour time and 2 hours of labour time. From the above information: (20 marks) < a. Calculate the amount of surplus value and s'. Show your steps of calculation clearly. b. Briefly explain the theoretical concepts of surplus value. (about 100 words)