2021 JMPSC Sprint Problems/Problem 17
Revision as of 16:15, 11 July 2021 by Mathdreams (talk | contribs)
Problem
What is the smallest positive multiple of that has no zeros in its decimal representation?
Solution
Notice that . Since always has zeros after it, we have to make sure has nonzero digits, so that the last 3 digits of the number doesn't contain a . We also need to make sure that has no zeros in its own decimal representation so that doesn't have any zeros other than the last digits. The smallest number that satisfies the above is , so the answer is .
~Mathdreams
~edited by tigerzhang
See also
The problems on this page are copyrighted by the Junior Mathematicians' Problem Solving Competition.