Girls in a class account for 50% of the class. After 6 girls are transferred from other places, the number of girls accounts for 4/7 of the class. How many students are there in the class?
某班女生占全班人数的50%，从外地转进6名女生后，女生人数占全班人数的(4/7)，全班原有学生多少人？
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

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

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

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

<gadget id="calculator">1 - (4/7)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(4/7) / (3/7)</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">(4/3) - 1</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">6 / (1/3) / (1/2)</gadget>
<output>36</output>

<result>36</result>