选择3:九分之五理由:女生比男生多25%,那么女生=(1+25%)男生,即女生=5/4男生,全班总人数为:5/4男生+男生=9/4男生,所以女生占全班人数的5/4男生/(9/4男生)=5/9个人观点,仅供参考