To solve this problem, we need to find the rate at which the farmer and his son plow the field together, and then use this rate to find the number of hours it will take the son to plow the field alone.
Let's call the rate at which the farmer and his son plow the field together R. We know that they can plow the field together in 8 hours, so:
R / 8 hours = 1 field
R / 12 hours = 1/3 field
To find the rate at which the son plows the field alone, we can divide the above equation by 2:
R / 24 hours = 1/3 field
R / 12 hours = 2/3 field
Therefore, it will take his son R/12 = 2/3 hours to plow the field alone. To reduce the answer to lowest terms, we can divide both the numerator and denominator by 2:
R/6 hours
Therefore, it will take the son R/6 = 1/3 hours to plow the field alone.