Xiaoming, Xiaohui, and Xiaoqiang are three friends in the same community. In a certain grade of elementary school, Xiaoming's age was the average of Xiaohui and Xiaoqiang. Now Xiao Ming has graduated from elementary school and has grown into a 13-year-old boy, and Xiao Hui is now 11 years old, so how old is Xiao Qiang now?
小明、小惠、小强是同一小区的三个小伙伴，在小学某年级时，小明的年龄是小惠和小强两人的平均数．现在小明小学毕业了，长成了一个13岁的少年，而小惠现在11岁，那么小强现在多少岁．
<gadget id="calculator">11 / 2</gadget>
<output>11/2 = around 5.5</output>

<gadget id="calculator">13 - (11/2)</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(15/2) / (1/2)</gadget>
<output>15</output>

<result>15</result>