How many methods are there to surround a rectangular chicken farm with a length of 25 meters and a width of 15 meters in an open space next to the wall? What is the minimum length of the fence?
在一边靠墙的空地里用篱笆围一块长25米，宽15米的长方形养鸡场，有几种围法？篱笆的长最少要多少米？
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<gadget id="calculator">25 + 30</gadget>
<output>55</output>

<result>55</result>