There is half a barrel of gasoline, and the total weight of the barrel is 8.9 kilograms. Continue to fill the barrel, and the total weight of the barrel is 16 kilograms. How much is the net weight of this barrel of gasoline?
有半桶汽油，连桶共重8.9千克，继续把桶装满，连桶共重16千克，这桶汽油净重多少千克？
<gadget id="calculator">16 - 8.9</gadget>
<output>7.1</output>

<gadget id="calculator">7.1 * 2</gadget>
<output>14.2</output>

<result>14.2</result>