   trailing 0's in factorial hundred The solution is wrong. The correct answer is 21 becuase the factors of squares of 5 ( 25,50,75) are already covered in the factors of 5. Chandrashekar Laveti Friday, May 2, 2003 I guess that 24 is correct .. Because 5 is only taken once when u consider the factors of 5 .... in  25,50 and 75 23 comes because 10 due to 5 in (  5, 15, 25, .... 95) 10 due to 0 in ( 10, 20 , ...... 100) 3 due to additional 5 in ( 25, 50 and 75) 1 due to additional 0 in 100 Rakesh Gupta Saturday, May 3, 2003 Hi Rakesh,       Thanks for responding. I just wanted to see how active this discussion board was! :) Chandu Chandrashekar Laveti Sunday, May 4, 2003 Just to add to discussion, there is a mechanical way for calculating trailing zeroes in a n!.There is a explicit formula for that.... If m is the number of trailing zeroes,then m=sum(i=1 to max) floor(n/5^i) where max = floor(ln(n) / ln(5)) Arun Iyer Sunday, June 1, 2003 The correct answer is 23! The reason is that the zeros generated by 50 are alreday accounted for. one Monday, June 23, 2003 Recent Topics Fog Creek Home