A cuboid fuel tank with a square bottom and a side length of 6 decimeters contains 144 liters of oil. It is known that the depth of the oil inside is half of the depth of the fuel tank. How deep is the fuel tank?
一个长方体油箱，底面是一个正方形，边长是6分米，里面已盛油144升，已知里面油的深度是油箱深度的一半，这个油箱深多少分米？
<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">144 / 36</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>