A chemical fertilizer factory plans to produce 3,000 tons of fertilizers this year, but actually produced 840 tons of fertilizers in the first three months. Based on this calculation, by what percentage can the excess production be achieved this year? (Solve with ratio)
某化肥厂，今年全年计划生产化肥3000吨，实际前3个月就生产化肥840吨，照这样计算，今年可超产百分之几？(用比例解)
<gadget id="calculator">840 / 3</gadget>
<output>280</output>

<gadget id="calculator">280 * 12</gadget>
<output>3_360</output>

<gadget id="calculator">3_360 - 3_000</gadget>
<output>360</output>

<gadget id="calculator">360 / 3_000</gadget>
<output>3/25 = around 0.12</output>

<result>3/25 = around 0.12</result>