There is a pile of stones on the construction site, 60% of them are removed in the first time, and 1/4 is removed in the second time, leaving 30 tons. How many tons are there in total in this pile of stones?
工地有一堆石子，第一次运走60%，第二次运走(1/4)，还剩下30吨，这堆石子共多少吨？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

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

<gadget id="calculator">1 - (3/5) - (1/4)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">30 / (3/20)</gadget>
<output>200</output>

<result>200</result>