关于一道典型数学比例题求解~~~

celineyo

DS. In a certain senior class, 72 percent of the male students and 80 percent of the female students have applied to college. What fraction of the students in the senior class are male ?
(1)There are 840 students in the senior class
(2)75 percent of the students in the senior class have applied to college

正确答案是B，一直没弄清怎么算，请大家帮忙~~~

zscsl

男的当中的70% 和女的当中的80%  录用了
给总数多少肯定不能求出来。。楼主想明白了吗？
B:
Male x Female Y
72%X+80%Y=75%(X+Y)
X Y 比例知道了。。当然男的占总体的就知道了

celineyo

明白了~~~谢谢你