The ratio of the number of boys to girls in the first semester of the sixth grade was 13:12. This semester, 2 girls were transferred, so that the number of girls accounted for exactly 50% of the class. How many girls were there in this class?
六年级一班上学期男生与女生人数人数的比是13：12，这学期又转来2名女生，使女生人数正好占全班人数的50%，这个班原有女生多少人？
<gadget id="calculator">2 * 13</gadget>
<output>26</output>

<gadget id="calculator">2 * 12</gadget>
<output>24</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 * (1/2) * 13</gadget>
<output>13</output>

<gadget id="calculator">2 * (1/2) * 12</gadget>
<output>12</output>

<gadget id="calculator">24 - 13 - 12</gadget>
<output>-1</output>

<gadget id="calculator">26 + (-1)</gadget>
<output>25</output>

<gadget id="calculator">(1/2) * 13</gadget>
<output>13/2 = around 6.5</output>

<gadget id="calculator">(1/2) * 12</gadget>
<output>6</output>

<gadget id="calculator">6 - 12</gadget>
<output>-6</output>

<gadget id="calculator">(13/2) + (-6)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">25 / (1/2)</gadget>
<output>50</output>

<gadget id="calculator">13 + 12</gadget>
<output>25</output>

<gadget id="calculator">12 / 25</gadget>
<output>12/25 = around 0.48</output>

<gadget id="calculator">50 * (12/25)</gadget>
<output>24</output>

<result>24</result>