是否能用老师的推导方式答题

问题如下：

If the current spot price of gold is USD 1,250, the one-year futures price of gold is USD 1,300, and the risk-free rate is 5% per annum (annually compounded), what is an estimate of the implied gold lease rate?

解释：

Let l be the implied gold lease rate (annually com-pounded). Then:

$1,300 = 1,250 * (\frac{1.05}{1+l})$

so that

l =1,250* 1.05/ 1,300 - 1 = 0.0096

that is, the implied lease rate is 0.96%.