There are two barrels of oil, A and B, and the difference in the amount of oil in the two barrels is 20 kg. (2/5) of oil in barrel A is equal to (1/2) of oil in barrel B. How many kilograms of oil is in barrel A?
有甲乙两桶油，两桶内的装油量的差是20千克．甲桶油量的(2/5)等于乙桶油量的(1/2)．甲桶有油多少千克．
<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">20 / 1</gadget>
<output>20</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<result>100</result>