The original batch of yellow sand on the construction site was used up (1/3), and another 3 tons were transported in. At this time, the yellow sand just accounted for 80% of the original yellow sand. How many tons of the original yellow sand were there on the construction site?
工地上原有一批黄沙，用去(1/3)后，又运进3吨，这时的黄沙正好占原有黄沙的80%，工地原有黄沙多少吨？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(4/5) - (2/3)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">3 / (2/15)</gadget>
<output>45/2 = around 22.5</output>

<result>45/2 = around 22.5</result>