There are several kilograms of coal in a warehouse, which can be used up in three days. (1/5) is used on the first day, the rest (2/5) is used on the second day, and the amount used on the third day is 18 kilograms less than the sum of the previous two days (3/2), how many kilograms of coal are there in total? ．
一仓库有煤若干千克，三天用完．第一天用去(1/5)，第二天用去余下的(2/5)，第三天用去的比前两天总和的(3/2)少18千克，则共有煤多少千克．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">(4/5) * (2/5)</gadget>
<output>8/25 = around 0.32</output>

<gadget id="calculator">(1/5) + (8/25)</gadget>
<output>13/25 = around 0.52</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(13/25) * (3/2)</gadget>
<output>39/50 = around 0.78</output>

<gadget id="calculator">1 - (1/5) - (8/25)</gadget>
<output>12/25 = around 0.48</output>

<gadget id="calculator">(39/50) - (12/25)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">18 / (3/10)</gadget>
<output>60</output>

<result>60</result>