5. (45 points) Given that the price of a stock is 100 yuan, the beta coefficient is 1.5, the discount rate of financing to buy the stock is beta coefficient multiplied by 1800 basis points, and the threshold value of guarantee maintenance rate A is 125%:

Please explain why the discount rate is a multiple of beta coefficient.

May I ask why the term of financing or securities lending can not be considered in the calculation of the aforementioned margin? In other words, why are the margin calculated according to the same formula every three or six months?

Please calculate the original margin ratio, financing percentage, leverage ratio and guarantee maintenance ratio of the stocks bought by financing.

Please calculate the original deposit that investors who buy 500 shares by financing and the amount borrowed from brokers.

Assuming that the stock price drops by 5%, please calculate the loss of investors who buy 500 shares by financing.