There are two barrels of oil, A and B, and there is 10 kilograms of oil in barrel A. If (1/2) is poured out from barrel A to barrel B, the ratio of oil in barrel A to barrel B is 1:7, and barrel B originally contained oil How many kilograms?
有甲、乙两桶油，甲桶有油10千克，如果从甲桶倒出(1/2)给乙桶，这时甲桶和乙桶油的比是1：7，乙桶原来有油多少千克？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">10 * (1/2)</gadget>
<output>5</output>

<gadget id="calculator">10 - 5</gadget>
<output>5</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">5 / (1/7)</gadget>
<output>35</output>

<gadget id="calculator">35 - 5</gadget>
<output>30</output>

<result>30</result>