A rectangular swimming pool has a circumference of 200 meters and a length of 60 meters. What is the width of the swimming pool in meters? (column equation solution)
长方形游泳池周长200米，长60米，游泳池宽是多少米？(列方程解答)
<gadget id="calculator">200 / 2</gadget>
<output>100</output>

<gadget id="calculator">100 - 60</gadget>
<output>40</output>

<result>40</result>