The Xingxing restaurant used 2/5 of the original coal and shipped in another 1200 kilograms. At this time, the coal in storage happened to be 2/3 of the original coal. How many tons of coal did the restaurant have?
星星酒家用去原有煤的(2/5)，又运来1200千克，这时存煤恰好是原有煤的(2/3)，这个酒家原有煤多少吨？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">2 / 5</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">(2/3) - (3/5)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1_200 / (1/15) / 1_000</gadget>
<output>18</output>

<result>18</result>