Pour out 70% of a barrel of oil, and then pour 10 kilograms. At this time, the weight ratio of the oil in the barrel to the original oil is 2:5. How many kilograms of oil are there in the original barrel?
一桶油倒出70%，再倒入10千克，这时桶里的油与原来油的重量的比是2：5，原来桶里有油多少千克？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

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

<gadget id="calculator">10 / (1/10)</gadget>
<output>100</output>

<result>100</result>