The weight difference between two barrels of oil, A and B, is 9 kilograms, and (1/5) of the weight of oil in barrel A is equal to (1/2) of the weight of barrel B, so what is the weight of barrel B in kilograms?
甲乙两桶油重量差为9千克，甲桶油重量的(1/5)等于乙桶油重量的(1/2)，则乙桶油重多少千克．
<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<result>6</result>