Two workers work together to assemble machine parts. There are now 30 parts in stock. Master A can produce 10 parts per hour, and Master B assembles 1 machine per hour, using 13 parts. After how many hours, all the parts in stock will be used up.
两个工人配合起来装配机器零件．现在有库存30个零件．甲师傅每小时能生产10个零件，乙师傅每小时装配1台机器，要用13个零件，多少小时后库存的零件全部用完．
<gadget id="calculator">13 - 10</gadget>
<output>3</output>

<gadget id="calculator">30 / 3</gadget>
<output>10</output>

<result>10</result>