Final answer:
Without the details of problem 20 provided, it's impossible to calculate the volume of the pyramid. For the practice problem, the weightlifter does 400 J of work to lift a 200 N barbell 2 m off the ground. None of the Option is correct.
Step-by-step explanation:
The question provided is asking about the volume of a pyramid, which is likely from a mathematics context. However, since the pyramid and its dimensions are not described in problem 20 within the provided information, it is impossible to give an accurate answer.
If this were a complete mathematics problem with the necessary information, one could use the formula for the volume of a pyramid, which is Volume = (1/3) × base area × height, to calculate the approximate volume in units³. To answer the question correctly, the dimensions of the base and the height would be required.
For the practice problem provided regarding the work done by a weightlifter, the concept used is from physics, and it involves calculating work using the formula Work = force × distance. The correct answer to the practice problem is 400 J since the weightlifter applies a force of 200 N to lift the barbell, and moves it through a distance of 2 m (Work = 200 N × 2 m = 400 J).