Knowing that the number of boys in the first class of the sixth grade of elementary school accounts for 70% of the total number of the class, the number of boys in the second class of the sixth grade is 2 less than that of the first class, and the number of girls is twice that of the first class. If the two classes are combined, the proportion of boys is 60%. May I ask: How many girls are there in the second class?
明知小学六年级一班男生的人数占全班总人数的70%，六年级二班的男生比一班男生少2名，而女生人数为一班女生的2倍．如果两班合在一起，则男生所占的比例为60%．请问：二班有多少名女生？
<gadget id="calculator">4 * 6</gadget>
<output>24</output>

<result>24</result>