[問題]GWD 02-02

[chulack]

Q2:

If n is a positive integer and the product of all the integers from 1 to n, inclusive, is divisible by 990, what is the least possible value of n?


A. 8

B. 9

C. 10

D. 11

E. 12

Answer:D


I'm confused..... :( Why the answer is not (B) 9? Since 990=9*10*11, so I thought 9 should be the least possible value of n.

[celivia]

Q2:

If n is a positive integer and the product of all the integers from 1 to n, inclusive, is divisible by 990, what is the least possible value of n?


A. 8

B. 9

C. 10

D. 11

E. 12

Answer:D


I'm confused..... :( Why the answer is not (B) 9? Since 990=9*10*11, so I thought 9 should be the least possible value of n.

您應該沒看清楚題目
n需要被990整除
也就是說n是9*10*11的倍數
其中11為質數,n至少要等於11,該數才能被990整除

[chulack]

oh...I got it. Thank you... ^_^