【GMAT数】all of the following have the same number of distinct prime factors except:20,21,24,30,45
问题描述：
【GMAT数】all of the following have the same number of distinct prime factors except:20,21,24,30,45
【GMAT数学】all of the following have the same number of distinct prime factors except:(A)20(B)21(C)24(D)30(E)45,
答案为什么是D
我的理解：20=2*2*5,21=3*7,24=2*2*2*3,30=2*3*5,45=3*3*5,
21,24,30,45的公因数3相同,所以选A,我错在哪儿?
答
the same number of distinct prime factors 意思是说数量,不是数字啦,D是有3个质数,其他都是两个,所以就是它了,数学它就是有时候跟你玩文字游戏的,要小心看题的啦~