In the theme activity of "Welcome to the Olympics", a certain school organized a recreational activity with the participation of all the faculty and staff. There are 9 more female employees than male employees participating in the activity, and the ratio of the number of female employees to male employees is 3:7. How many female employees participated in the activity in this school?
在"迎奥运"的主题活动中，某校组织了一次全体教职工参加的文娱活动．参加活动的女职工比男职工多9人，女职工比男职工多的人数与男职工的比是3：7，这个学校参加活动的女职工有多少人？
<gadget id="calculator">9 * 7</gadget>
<output>63</output>

<gadget id="calculator">63 / 3</gadget>
<output>21</output>

<gadget id="calculator">21 + 9</gadget>
<output>30</output>

<result>30</result>