If C=number of children, then the total number of adults=C+600.
Total attendance=C+C+600=2C+600.
Add together the ratios: 3+4+2=9.
We can therefore work out how many men women and children there were:
Men=3(2C+600)/9=(2C+600)/3
Women=4(2C+600)/9
Children=C=2(2C+600)/9.
So 9C=4C+1200, 5C=1200, C=240.
Attendance=2C+600=480+600=1080.
Men=360
Women=480
Children=240.
Ratio of girls to boys is 1:3. 1+3=4 so ¼ of 240=60 are girls and ¾ of 240=180 are boys.
SUMMARY
Men=360
Women=480
Girls=60
Boys=180
Total=360+480+60+180=1,080.