A rectangular garden with a width of 3.2m is enclosed by a fence with a length of 15m and one side against the wall. What is the maximum area of it?
用长15m的篱笆一面靠墙围成一个宽3.2m的长方形花园，它的面积最大是多少平方米？
<gadget id="calculator">3.2 * 2</gadget>
<output>6.4</output>

<gadget id="calculator">15 - 6.4</gadget>
<output>8.6</output>

<gadget id="calculator">8.6 * 3.2</gadget>
<output>27.52</output>

<result>27.52</result>