For a batch of coal, 32% is used up, which is exactly (9/10) tons. How many tons was this batch of coal originally?
一批煤，用去32%刚好是(9/10)吨，这批煤原来多少吨？
<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">32 / 100</gadget>
<output>8/25 = around 0.32</output>

<gadget id="calculator">(9/10) / (8/25)</gadget>
<output>45/16 = around 2.8125</output>

<result>45/16 = around 2.8125</result>