6 Of the positive integers that are multiples of 30 and are less than or equal to 360,what fraction are multiples of 12?
a.1/6 b.1/5 c.1/3 d.2/5 e.1/2
首先这道题我是对multilples of ....不大明白,这是什么意思啊?其次这道题怎么解呢?
在小于360的30的公倍数中,也是12的公倍数的占多少?30N≤360, 得N≤12,所以共有12个数满足题干.
又12与30的最小公倍数为60,其实此题是求是60的倍数又小于等于360所占比例,同理求出为6
所以,6/12=答案E
7 A certain teacher has a total ofat least 110 students enrolled in her classes.if the teachers has anaverage (arithmetic mean) of exactly 27 students enrolled per class.what is the least possible number of classes that the teacher couldhave?
a.3 b.4 c.5 d.6 e.7
我觉得这道题就是用110除以27就好了,可是答案是选c的
是呀，110/27=4.04,如果是4个班，那么总人数为108，还剩2个。当然是5个班了。
