MathDB
Lots of 9s

Source:

January 1, 2009

Problem Statement

The arithmetic mean of the nine numbers in the set {9,99,999,9999,...,999999999} \{9,99,999,9999, . . . ,999999999\} is a 9 9-digit number M M, all of whose digits are distinct. The number M M does not contain the digit <spanclass=latexbold>(A)</span> 0<spanclass=latexbold>(B)</span> 2<spanclass=latexbold>(C)</span> 4<spanclass=latexbold>(D)</span> 6<spanclass=latexbold>(E)</span> 8 <span class='latex-bold'>(A)</span>\ 0 \qquad <span class='latex-bold'>(B)</span>\ 2 \qquad <span class='latex-bold'>(C)</span>\ 4 \qquad <span class='latex-bold'>(D)</span>\ 6 \qquad <span class='latex-bold'>(E)</span>\ 8