Girls accounted for (4/9) in the classroom, and 2 more girls came in later, so that the proportion of girls increased to (9/19), how many people are there in the classroom now?
教室里女生占(4/9)，后来又进来2名女生，这样使女生所占比例上升为(9/19)，现在教室里共有多少人．
<gadget id="calculator">9 / 19</gadget>
<output>9/19 = around 0.473684</output>

<gadget id="calculator">(9/19) * 2</gadget>
<output>18/19 = around 0.947368</output>

<gadget id="calculator">2 - (18/19)</gadget>
<output>20/19 = around 1.052632</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(9/19) - (4/9)</gadget>
<output>5/171 = around 0.02924</output>

<gadget id="calculator">(20/19) / (5/171)</gadget>
<output>36</output>

<gadget id="calculator">36 + 2</gadget>
<output>38</output>

<result>38</result>