【Answer】Solution: $(25-1) \times[(3-1) \div(5-1)]+1$,
$$
\begin{array}{l}
=24 \times \frac{1}{2}+1, \\
=12+1, \\
=13 \text { (floors), }
\end{array}
$$

Answer: When Xiao Li reaches the 25th floor, Xiao Hua reaches the 13th floor.
Therefore, the answer is: 13.
8. (3 points) Xiao Li and Xiao Hua are competing in a stair-climbing race. When Xiao Li reaches the 5th floor, Xiao Hua is exactly at the 3rd floor. According to this calculation, when Xiao Li reaches the 25th floor, Xiao Hua will be at the $\qquad$ floor.