The ratio of the number of girls to the number of boys in Class 51 is 3:4, the number of students in Class 51 is 28% of the whole grade, and the number of girls in Class 51 is the number of students in the whole grade
五1班女生人数和男生人数的比是3：4，五1班学生人数是全年级的28%，五1班女生人数是全年级人数的多少
<gadget id="calculator">28 / 100</gadget>
<output>7/25 = around 0.28</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(7/25) * (3/7)</gadget>
<output>3/25 = around 0.12</output>

<result>3/25 = around 0.12</result>