Let the observations $x_i$ ($1 \le i \le 10$) satisfy the equations $\sum_{i=1}^{10}(x_i - 5) = 10$ and $\sum_{i=1}^{10}(x_i - 5)^2 = 40$. If $\mu$ and $\sigma^2$ are the mean and the variance of the observations $x_1^3, x_2^3, \ldots, x_{10}^3$, then the ordered pair $(\mu, \sigma^2)$ is equal to: