barrel of oil weighs 4.6 kilograms. After pouring out (1/3) of the oil, the weight of the barrel is 3.1 kilograms. How many kilograms of oil are there in the barrel?
一桶油连油重4.6千克，倒出(1/3)油后，连桶重3.1千克，桶里原来有油多少千克．
<gadget id="calculator">4.6 - 3.1</gadget>
<output>1.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1.5 / (1/3)</gadget>
<output>4.5</output>

<result>4.5</result>