MathDB
2010 AMC 8 - Problem 17 - Find the ratio XQ/QY

Source:

May 27, 2011
ratiogeometryBad Asymptote

Problem Statement

The diagram shows an octagon consisting of 1010 unit squares. The portion below PQ\overline{PQ} is a unit square and a triangle with base 55. If PQ\overline{PQ} bisects the area of the octagon, what is the ratio XQQY\frac{XQ}{QY}?
[asy] import graph; size(300); real lsf = 0.5; pen dp = linewidth(0.7) + fontsize(10); defaultpen(dp); pen ds = black; pen xdxdff = rgb(0.49,0.49,1); draw((0,0)--(6,0),linewidth(1.2pt)); draw((0,0)--(0,1),linewidth(1.2pt)); draw((0,1)--(1,1),linewidth(1.2pt)); draw((1,1)--(1,2),linewidth(1.2pt)); draw((1,2)--(5,2),linewidth(1.2pt)); draw((5,2)--(5,1),linewidth(1.2pt)); draw((5,1)--(6,1),linewidth(1.2pt)); draw((6,1)--(6,0),linewidth(1.2pt));draw((1,1)--(5,1),linewidth(1.2pt)); draw((1,1)--(1,0),linewidth(1.2pt));draw((2,2)--(2,0),linewidth(1.2pt)); draw((3,2)--(3,0),linewidth(1.2pt)); draw((4,2)--(4,0),linewidth(1.2pt)); draw((5,1)--(5,0),linewidth(1.2pt)); draw((0,0)--(5,1.5),linewidth(1.2pt)); dot((0,0),ds); label("PP", (-0.23,-0.26),NE*lsf); dot((0,1),ds); dot((1,1),ds); dot((1,2),ds); dot((5,2),ds); label("XX", (5.14,2.02),NE*lsf); dot((5,1),ds); label("YY", (5.12,1.14),NE*lsf); dot((6,1),ds); dot((6,0),ds); dot((1,0),ds); dot((2,0),ds); dot((3,0),ds); dot((4,0),ds); dot((5,0),ds); dot((2,2),ds); dot((3,2),ds); dot((4,2),ds); dot((5,1.5),ds); label("QQ", (5.14,1.51),NE*lsf); clip((-4.19,-5.52)--(-4.19,6.5)--(10.08,6.5)--(10.08,-5.52)--cycle); [/asy]
<spanclass=latexbold>(A)</span> 25<spanclass=latexbold>(B)</span> 12<spanclass=latexbold>(C)</span> 35<spanclass=latexbold>(D)</span> 23<spanclass=latexbold>(E)</span> 34<span class='latex-bold'>(A)</span>\ \frac 25 \qquad <span class='latex-bold'>(B)</span>\ \frac 12 \qquad <span class='latex-bold'>(C)</span>\ \frac 35 \qquad <span class='latex-bold'>(D)</span>\ \frac 23 \qquad <span class='latex-bold'>(E)</span>\ \frac 34