There is a barrel of oil, 60% of the oil is used, and another 10kg is poured in. At this time, the oil in the barrel is 60% of the original amount. How many kilograms of oil was originally contained in the barrel?
有一桶油，用去油的60%，又倒入10kg，这时桶里的油是原来的60%，这个桶原来装多少千克油？
<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">(3/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">10 / (1/5)</gadget>
<output>50</output>

<result>50</result>