It is known that the number of students in school A is 40% of the number of students in school B, the number of girls in school A is 30% of the number of students in school A, and the number of boys in school B is 42% of the number of students in school B. Then, the number of girls in the two schools accounts for two % of the total number of students.
已知甲校学生数是乙校学生数的40%，甲校女生数是甲校学生数的30%，乙校男生数是乙校学生数的42%，那么，两校女生数占两校学生总数的百分之多少．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(2/5) * (3/10)</gadget>
<output>3/25 = around 0.12</output>

<gadget id="calculator">42 / 100</gadget>
<output>21/50 = around 0.42</output>

<gadget id="calculator">1 - (21/50)</gadget>
<output>29/50 = around 0.58</output>

<gadget id="calculator">(3/25) + (29/50)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">(7/10) / (7/5)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>