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7^m is a factor of n/7^2?

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by sanju09 » Mon Mar 12, 2012 2:33 am
If n is the product of the integers from 1 to 70, inclusive, what is the greatest integer m for which 7^m is a factor of n/7^2?
(A) 2
(B) 7
(C) 9
(D) 11
(E) 14
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Source: — Problem Solving |

by killer1387 » Mon Mar 12, 2012 2:55 am
sanju09 wrote:If n is the product of the integers from 1 to 70, inclusive, what is the greatest integer m for which 7^m is a factor of n/7^2?
(A) 2
(B) 7
(C) 9
(D) 11
(E) 14
Total number of 7 in 70!=11
hence n/7^2 has 11-2 =9 7's

option C.
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