There was an original batch of cement on the construction site. After 60% of it was used up, another 25 tons were shipped in. At this time, the ratio of the cement on the construction site to the original cement tonnage was 4:5. How many tons of cement were there originally on the construction site?
工地上原有一批水泥，用去了它的60%后，又运来25吨，这时工地上的水泥与原来水泥吨数的比是4：5，工地上原来有水泥多少吨？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(4/5) - (2/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">25 / (2/5)</gadget>
<output>125/2 = around 62.5</output>

<result>125/2 = around 62.5</result>