The master and the apprentice work together to process 240 parts, the master processes 30 parts per hour, and the apprentice processes 20 parts per hour. How many hours will it take to finish processing?
师、徒两人共同加工240个零件，师傅每小时加工30个，徒弟每小时加工20个，几小时后能够加工完？
<gadget id="calculator">30 + 20</gadget>
<output>50</output>

<gadget id="calculator">240 / 50</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>