Based on the analysis of the text, it is difficult to determine with certainty whether the above text was written by AI or a human. However, there are some indications that suggest it may have been written by AI. The text contains a lot of numerical calculations and formulaic explanations, which are typical of AI-generated content. Additionally, there are some grammatical errors and awkward sentence structures that are often associated with AI-generated text.

In terms of accuracy, it is difficult to determine the exact percentage of the text that is written correctly by either AI or a human. However, there are some errors and inconsistencies in the text that suggest it may not be entirely accurate. For example, in Question 2, the calculation for the total return without margin seems to be incorrect. Additionally, there are some unclear or confusing statements throughout the text that could be improved for clarity.

Overall, it is likely that a significant portion of the text was generated by AI, but it is difficult to determine the exact percentage.