The perimeter of a square is equal to the perimeter of a rectangle. The side length of the square is 20 cm and the width of the rectangle is 15 cm. What is the length of the rectangle in cm?
一个正方形周长和一个长方形的周长相等，正方形的边长是20厘米，长方形的宽是15厘米，求这个长方形的长是多少厘米？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">40 - 15</gadget>
<output>25</output>

<result>25</result>