MathDB
Product of Three Primes

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January 2, 2009
number theoryprime numbers

Problem Statement

Let n n be the largest integer that is the product of exactly 3 3 distinct prime numbers, d d, e e, and 10d\plus{}e, where d d and e e are single digits. What is the sum of the digits of n n? <spanclass=′latex−bold′>(A)</span> 12<spanclass=′latex−bold′>(B)</span> 15<spanclass=′latex−bold′>(C)</span> 18<spanclass=′latex−bold′>(D)</span> 21<spanclass=′latex−bold′>(E)</span> 24 <span class='latex-bold'>(A)</span>\ 12 \qquad <span class='latex-bold'>(B)</span>\ 15 \qquad <span class='latex-bold'>(C)</span>\ 18 \qquad <span class='latex-bold'>(D)</span>\ 21 \qquad <span class='latex-bold'>(E)</span>\ 24
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