Xiao Ming used a 3-meter-long bamboo pole to measure the depth of the swimming pool. He first inserted one end of the bamboo pole into the water, and made a mark where the water surface touched the bamboo pole. Make a mark at the position of the bamboo pole. If the distance between the two marks is 0.2 meters, do you know how many meters the swimming pool is?
小明用一根3米长的竹竿去测量游泳池的深度，他先把竹竿的一端插入水中，在水面碰到竹竿的位置做了一个记号，他再把竹竿掉过头来插入水中，又在水面碰到竹竿的位置做一个记号，如果这两个记号之间相隔0.2米，你知道游泳池有多少米吗？
<gadget id="calculator">3 - 0.2</gadget>
<output>2.8</output>

<gadget id="calculator">2.8 / 2</gadget>
<output>1.4</output>

<result>1.4</result>