A pile of coal, 25% of this pile of coal is used for the first time, 35% of this pile of coal is used for the second time, and 5 tons more are used for the second time than the first time, how many tons of this pile of coal are there?
一堆煤，第一次用去这堆煤的25%，第二次用去这堆煤的35%，第二次比第一次多用去了5吨，这堆煤有多少吨？
<gadget id="calculator">35 / 100</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(7/20) - (1/4)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">5 / (1/10)</gadget>
<output>50</output>

<result>50</result>