4. (5 points) In the classroom, there are several students, and their average age is 8 years old. If we add Teacher Li's age, their average age becomes 11 years old. It is known that Teacher Li's age is 32 years old. Therefore, there are $\qquad$ people in the classroom.
【Solution】Solve: $(32-11) \div(11-8)+1$
$$
\begin{array}{l}
=21 \div 3+1 \\
=8 \text { (people) }
\end{array}
$$

Answer: There are a total of 8 people in the classroom.
Therefore, the answer is: 8.