GWD题：if M is the 求解析

缺氧 · 发表于 2011-1-24 05:11:06

If M is the least common multiple of 90, 196, and 300, which of the following is NOT a factor of M?

A. 600
B. 700
C. 900
D. 2,100
E. 4,900

我不明白为什么底下的LCM是那几个数相乘 thanks
90 = 2*3*3*5
196=2*2*7*7
300=2*2*3*5*5

LCM = 2*2*3*3*5*5*7*7 this is the number M.

now check each number whether a factor of M.

Answer is 600.

sdcar2010 · 发表于 2011-1-24 05:27:22

LCM, by definition, is a multiple of a group of numbers. Google its definition and the method to arrive at the right LCM from a group of numbers.

缺氧 · 发表于 2011-1-24 06:19:00

还是不明白，我不知道LCM是怎么得来的，求解析谢谢了

sdcar2010 · 发表于 2011-1-24 06:41:59

2 | 90 196 300
2 | 45 98 150
3 | 45 49 75
5 | 15 49 25
3 49 5

LCM = 2*2*3*3*5*5*7*7 this is the number

缺氧 · 发表于 2011-1-24 22:33:21

我明白了，谢谢你啊。太感谢了

kira_ke · 发表于 2017-4-1 21:41:19

GWD题：if M is the 求解析

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