8.10 Each of 10 people has a bucket to fill with water. Let the time it takes for the tap to fill the bucket of the $i$-th person be $t_{i}$. Assume these $t_{i}$ are all different. When there is only one tap, how should the order of the 10 people be arranged so that the total waiting time for the 10 people is minimized?
8. Let's assume $t_{1}9>8>\cdots>2>1$, so by the rearrangement inequality, the minimum value is $10 t_{1}+9 t_{2}+\cdots+t_{10}$, which means starting with the person who spends the least time, followed by the next, until the person who spends the most time finishes.