The worker uncle binds books, 300 books per hour, and the binding is completed in 5 hours. If it takes 2.5 hours to finish binding, how many copies will be bound per hour?
工人叔叔装订书本，每小时装订300本，5小时装订完．如果用2.5小时装订完，每小时要装订多少本？
<gadget id="calculator">5 / 2.5</gadget>
<output>2</output>

<gadget id="calculator">300 * 2</gadget>
<output>600</output>

<result>600</result>