A certain county produced 42,000 tons of wheat last autumn, which was 40% more than the previous year. How many tons of wheat was produced in the autumn of the previous year?
某县去年秋季产小麦4.2万吨，去年比前年增产四成，前年秋季产小麦多少万吨？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">4.2 / (7/5)</gadget>
<output>3</output>

<result>3</result>