A trapezoidal billboard with an upper base of 10 meters, a lower base of 15 meters and a height of 20 meters. If 2 kilograms of paint are painted per square meter, how many kilograms of paint are needed to paint the front and back sides of the billboard?
一块梯形广告牌，上底10米，下底15米，高20米．如果每平方米刷漆2千克，那么将这个广告牌正反两面刷漆，需要多少千克油漆．
<gadget id="calculator">10 + 15</gadget>
<output>25</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">25 * 10 * 2 * 2</gadget>
<output>1_000</output>

<result>1_000</result>