after 2 females leave a party ,there are twice as many males as females.then 9 males leave and there

题目

after 2 females leave a party ,there are twice as many males as females.then 9 males leave and there are twice as many femails as males.The totle number of prople left at the party after the 9 males leave.
twice as many ..as 到底是谁是谁两倍,

答案

twice as many males as females男人是女人的两倍多.
从后面推起,原来男为女的2倍,离开九人后男为女的一半,设男为X个女为Y个,9=3/2（Y-2）,Y=8
Y-2=X/2,所以X=12.