The advertising company needs to paint a layer of white paint on a trapezoidal billboard with an upper base of 8 meters, a lower base of 12 meters and a height of 5 meters. If 0.6 kilograms of paint is used per square meter, how many kilograms of paint are needed to finish the billboard?
广告公司要为一个梯形的广告牌涂一层白色油漆，上底8米，下底12米，高5米．如果每平方米用油漆0.6千克，涂完这个广告牌需要多少千克油漆？
<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">20 * (5/2) * 0.6</gadget>
<output>30</output>

<result>30</result>