Dark Mousy Posted December 31, 2009 Report Share Posted December 31, 2009 How many zeroes are at the end of the following product? 2010 x 2009 x 2008 ... x 5 x 4 x 3 x 2 x 1? 2 REPS to whoever solves the riddle! Link to comment Share on other sites More sharing options...
Deustodo Posted December 31, 2009 Report Share Posted December 31, 2009 42! Link to comment Share on other sites More sharing options...
Alexis Rhodes Posted December 31, 2009 Report Share Posted December 31, 2009 Say hello to the calculator :) Is it 2 ? Link to comment Share on other sites More sharing options...
Catman25 Posted December 31, 2009 Report Share Posted December 31, 2009 Well it's 9.730181664e11 so I'm gonna guess eleven, even though rounding and this notation's probably throwing me off. Link to comment Share on other sites More sharing options...
Dark Mousy Posted December 31, 2009 Author Report Share Posted December 31, 2009 All incorrect! I made it so you can't do it on a calculator. The ... means every number inbetween that. Link to comment Share on other sites More sharing options...
Skuldur Posted December 31, 2009 Report Share Posted December 31, 2009 Infinite. =O Link to comment Share on other sites More sharing options...
Catman25 Posted December 31, 2009 Report Share Posted December 31, 2009 I can just change the notation on my calculator to show all the places you know. =/ Link to comment Share on other sites More sharing options...
Alexis Rhodes Posted December 31, 2009 Report Share Posted December 31, 2009 lol if you cant use a calculator and you made it up then the whole questions and answer must be wrong Link to comment Share on other sites More sharing options...
Silent Omega Posted December 31, 2009 Report Share Posted December 31, 2009 Infinite. =O Link to comment Share on other sites More sharing options...
Skuldur Posted December 31, 2009 Report Share Posted December 31, 2009 32664030 zeros. =O Link to comment Share on other sites More sharing options...
Mindscatter Posted December 31, 2009 Report Share Posted December 31, 2009 The number of zeros are equal to how many times 2X5 (as a product) repeats in the sequence. More accurately, how many times 5 (as a product), because 2 appears too many times, appears in the sequence. So you do this: [2010:5]=a[2010:25]=b[2010:125]=c[2010:625]=d And the number of zeros is a+b+c+d You can easily calculate a,b,c and d. And if you add them up, you get the result. Easy. Link to comment Share on other sites More sharing options...
Dark Mousy Posted December 31, 2009 Author Report Share Posted December 31, 2009 The number of zeros are equal to how many times 2X5 (as a product) repeats in the sequence. More accurately' date=' how many times 5 (as a product), because 2 appears too many times, appears in the sequence. So you do this: [2010:5']=a[2010:25]=b[2010:125]=c[2010:625]=d And the number of zeros is a+b+c+d You can easily calculate a,b,c and d. And if you add them up, you get the result. Easy. Very nice. Link to comment Share on other sites More sharing options...
Mindscatter Posted December 31, 2009 Report Share Posted December 31, 2009 The result is 501 Link to comment Share on other sites More sharing options...
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