factory rushes to produce a batch of accessories. After producing 250 pieces, the production efficiency is doubled by improving the technology. Now the production time of 300 pieces is 10 hours less than that of 250 pieces of stone. The original production per hour How many accessories? (column equation solution)
某厂赶制一批配件，生产了250个以后，经改进技术使生产效率提高到原来的2倍，现在生产300个的时间比石料生产250个的时间还少10小时，问原来每小时生产配件多少个？(列方程解答)
<gadget id="calculator">250 * 2</gadget>
<output>500</output>

<gadget id="calculator">500 - 300</gadget>
<output>200</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">200 / 20</gadget>
<output>10</output>

<result>10</result>