Final answer:
The specific gravity of the oil is approximately 3.59.
Step-by-step explanation:
To calculate the specific gravity of the oil, we need to use the formula: Specific Gravity = Weight in Air / (Weight in Air - Weight in Liquid)
Given that the weight of the plummet in air is 12.64 g, the weight when immersed in water is 8.57 g, and the weight when immersed in oil is 9.12 g, we can substitute these values into the formula:
Specific Gravity = 12.64 g / (12.64 g - 9.12 g) = 12.64 g / 3.52 g = 3.5909...
Rounding this value to two decimal places, the specific gravity of the oil is approximately 3.59.