The canteen of the factory uses 40% of the original coal and then transports 1,200 kilograms. At this time, the amount of coal stored is just 2/3 of the original coal. How many kilograms of the original coal?
工厂食堂用去原有煤的40%后又运来1200千克，这时存煤量恰好是原存煤的(2/3)，原有煤多少千克？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/3) - (2/5)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">1_200 / (4/15)</gadget>
<output>4_500</output>

<result>4_500</result>