A pile of coal, 40% of the first time was used, and 1/4 of the original total amount was used for the second time, leaving 14 tons left. How many tons is this pile of coal?
一堆煤，第一次用去40%，第二次用去原来总量的(1/4)，还剩余14吨．这堆煤共有多少吨？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">14 / (7/20)</gadget>
<output>40</output>

<result>40</result>