A pile of coal, after 40% of the total amount has been transported away, another 240 tons are brought in. At this time, the total amount of stored coal is less than the total amount of the original pile (1/5). How many tons was this pile of coal originally?
一堆煤，运走总数的40%后，又运来240吨，这时存煤总数比原来这堆煤的总数少(1/5)．这堆煤原来有多少吨？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (1/5) - (3/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">240 / (1/5)</gadget>
<output>1_200</output>

<result>1_200</result>