MathDB
1994 AMC 12 #20

Source:

December 30, 2011
ratioquadraticsgeometric sequencearithmetic sequenceAMC

Problem Statement

Suppose x,y,zx,y,z is a geometric sequence with common ratio rr and x≠yx \neq y. If x,2y,3zx, 2y, 3z is an arithmetic sequence, then rr is
<spanclass=′latex−bold′>(A)</span> 14<spanclass=′latex−bold′>(B)</span> 13<spanclass=′latex−bold′>(C)</span> 12<spanclass=′latex−bold′>(D)</span> 2<spanclass=′latex−bold′>(E)</span> 4 <span class='latex-bold'>(A)</span>\ \frac{1}{4} \qquad<span class='latex-bold'>(B)</span>\ \frac{1}{3} \qquad<span class='latex-bold'>(C)</span>\ \frac{1}{2} \qquad<span class='latex-bold'>(D)</span>\ 2 \qquad<span class='latex-bold'>(E)</span>\ 4
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