10. (5%) Assume that Mary and Danny have the utility function and wealth levels as specified in question 9, and Mary will face the same risky bundle stated in question 9 as well. However, Danny now faces no risk at all. Suppose that Mary offers to pay Danny \( R > 0 \) to bear her risk of losing $7,500. Mary will pay Danny \( R \) whether or not she suffers the loss. If Mary loses $7,500, Danny must pay her $7,500. Under the circumstance, the lower bound of \( R \) is _(10a)_ and the upper bound of \( R \) is _(10b)_ so that Mary and Danny will agree this arrangement.