2. (6 points) A certain duplicator can print 3600 sheets of paper per hour, so printing 240 sheets of paper requires $\qquad$ minutes.
【Analysis】Convert 1 hour $=60$ minutes, first based on work efficiency $=$ total work $\div$ working time, find out the work efficiency of the duplicator, then according to working time $=$ total work $\div$ work efficiency to solve the problem.

【Solution】Solution: 1 hour $=60$ minutes,
$$
\begin{array}{l}
240 \div(3600 \div 60), \\
=240 \div 60, \\
=4 \text { (minutes), }
\end{array}
$$

Answer: It takes 4 minutes to print 240 sheets of paper.
Therefore, the answer is: 4.
【Comment】This question mainly examines students' ability to solve problems based on the quantitative relationship between working time, work efficiency, and total work.