MathDB
Mean of Conditional 5-Digit Numbers

Source:

January 14, 2009

Problem Statement

What is the average (mean) of all 5 5-digit numbers that can be formed by using each of the digits 1 1, 3 3, 5 5, 7 7, and 8 8 exactly once? <spanclass=′latex−bold′>(A)</span> 48000<spanclass=′latex−bold′>(B)</span> 49999.5<spanclass=′latex−bold′>(C)</span> 53332.8<spanclass=′latex−bold′>(D)</span> 55555<spanclass=′latex−bold′>(E)</span> 56432.8 <span class='latex-bold'>(A)</span>\ 48000\qquad <span class='latex-bold'>(B)</span>\ 49999.5\qquad <span class='latex-bold'>(C)</span>\ 53332.8\qquad <span class='latex-bold'>(D)</span>\ 55555\qquad <span class='latex-bold'>(E)</span>\ 56432.8
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