barrel of gasoline with barrels weighs 16 kilograms. After pouring out half of the gasoline, the remaining gasoline with barrels weighs 8.5 kilograms. How many kilograms does a gasoline can weigh?
一桶汽油连桶重16千克，倒出一半汽油后，剩下的汽油连桶重8.5千克．汽油桶重多少千克？
<gadget id="calculator">16 - 8.5</gadget>
<output>7.5</output>

<gadget id="calculator">7.5 * 2</gadget>
<output>15</output>

<gadget id="calculator">16 - 15</gadget>
<output>1</output>

<result>1</result>