There are two barrels of oil, A and B, and A has 40 kilograms of oil. If (1/3) of the oil is poured from B into A, then A and B have the same amount of oil. How much is a barrel of original oil in kilograms?
有甲，乙两桶油，甲桶有油40千克，如果从乙桶中倒出(1/3)的油到甲桶，那么甲乙两桶中的油一样多．乙桶原有油多少千克？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">40 / (1/3)</gadget>
<output>120</output>

<result>120</result>