The oil in barrel A is 3.6 kg more than that in barrel B. If 1 kg is taken out from each of the two barrels, the remaining (2/21) in barrel A is equal to the remaining (1/7) in barrel B, then the original oil in barrel A How many kilograms.
甲桶油比乙桶油多3.6千克，如果从两桶中各取出1千克后，甲桶剩下的(2/21)等于乙桶剩下的(1/7)，那么甲桶原有油多少千克．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">3.6 * (1/7)</gadget>
<output>0.514286</output>

<gadget id="calculator">2 / 21</gadget>
<output>2/21 = around 0.095238</output>

<gadget id="calculator">(1/7) - (2/21)</gadget>
<output>1/21 = around 0.047619</output>

<gadget id="calculator">0.514286 + (1/21)</gadget>
<output>0.561905</output>

<gadget id="calculator">0.561905 / (1/21)</gadget>
<output>11.800005</output>

<result>11.800005</result>