The two piles of yellow sand are 5.7 tons in total, the first pile is used (3/4), the second pile is used (3/5), and the rest of the two piles are combined, which is less than the original first pile (1/ 5), how many tons are there in the first pile?
两堆黄沙共5.7吨，第一堆用去(3/4)，第二堆用去(3/5)，把两堆剩下的合在一起，比原来第一堆还少(1/5)，原来第一堆有多少吨？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">1 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

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

<gadget id="calculator">(11/20) / (2/5)</gadget>
<output>11/8 = around 1.375</output>

<gadget id="calculator">1 + (11/8)</gadget>
<output>19/8 = around 2.375</output>

<gadget id="calculator">5.7 / (19/8)</gadget>
<output>2.4</output>

<result>2.4</result>