A barrel of oil, half of the oil is poured out each time, and the barrel weighs 8 kilograms after being poured three times. It is known that the barrel weighs 1.5 kilograms. How many kilograms of oil are in the barrel?
一桶油，每次倒掉油的一半，倒了三次后连桶重8千克，已知桶重1.5千克，原来桶里有油多少千克？
<gadget id="calculator">8 - 1.5</gadget>
<output>6.5</output>

<gadget id="calculator">6.5 * 2 * 2 * 2</gadget>
<output>52</output>

<result>52</result>