For a rectangular swimming pool, it takes 480 meters to walk twice along the swimming pool. If the length of the swimming pool is 100 meters, what is the width in meters?
一个长方形的游泳池，沿着游泳池走两圈要480米，若游泳池的长是100米，宽是多少米．
<gadget id="calculator">480 / 2 / 2</gadget>
<output>120</output>

<gadget id="calculator">120 - 100</gadget>
<output>20</output>

<result>20</result>