barrel of oil weighs 35 kilograms, and the weight of the barrel after pouring out half is 24 kilograms. How much does the barrel weigh?
一桶油连桶重35千克，倒出一半后连桶重24千克，这只油桶重多少千克．
<gadget id="calculator">35 - 24</gadget>
<output>11</output>

<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<gadget id="calculator">35 - 22</gadget>
<output>13</output>

<result>13</result>