A rectangle has a length of 20 decimeters and a width of 75% of its length. What is the perimeter of this rectangle in decimeters?
一个长方形，长为20分米，宽是长的75%，这个长方形的周长是多少分米．
<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">20 * (3/4)</gadget>
<output>15</output>

<gadget id="calculator">20 + 15</gadget>
<output>35</output>

<gadget id="calculator">35 * 2</gadget>
<output>70</output>

<result>70</result>