Two round logs of the same texture are placed on the construction site. The radius of the bottom surface of A log is twice that of B log, and the length of B log is twice that of A log. The captain asked the technician to weigh the two pieces of wood. The technician only weighed the weight of wood B, which weighed 30 kilograms, and then said to the captain: "You can know the weight of wood A without weighing it." Please calculate the weight of wood A.
工地上放着两根质地相同的圆往形木料，甲木料的底面半径是乙木料的2倍，乙木料的长度是甲木料的2倍．队长让技术员称一称两根木料的质量．技术员只称得乙木料重30千克，然后跟队长说："甲木料不用称也知道有多重．"请你算一算甲木料有多重．
<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<result>60</result>