After a bucket of environmentally friendly paint is used to paint the wall (3/5), another 12 kg is added. At this time, the paint in the bucket is exactly (1/2) of the whole bucket of paint. How many kilograms does this bucket of environmentally friendly paint have?
一桶环保油漆刷墙用去(3/5)后，又加进12千克，这时桶里的油漆正好是全桶油漆的(1/2)，这桶环保油漆原有多少千克？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 / 5</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">(1/2) - (2/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">12 / (1/10)</gadget>
<output>120</output>

<result>120</result>