There is a barrel of oil that takes out 2.1 kilograms for the first time, and the remaining 25% for the second time. At this time, there are still 7.5 kilograms in the barrel. How many kilograms are there in the barrel?
有一桶油第一次取出2.1千克，第二次取出余下的25%．这时桶里还有7.5千克，这桶袖原来有多少千克？
<gadget id="calculator">7.5 + 1.575</gadget>
<output>9.075</output>

<gadget id="calculator">9.075 / 0.75</gadget>
<output>12.1</output>

<result>12.1</result>