A certain factory saved 10% of coal last year compared with the previous year, saving a total of 200,000 tons of coal. How many tons of coal was used in the previous year?
某工厂去年比前年节约用煤10%，共节约用煤20万吨，前年用煤多少万吨？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">20 / (1/10)</gadget>
<output>200</output>

<result>200</result>