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MATH / Regions A,B,C,J and K represent ponds. Logs leave pond A and float down flumes (represented by arrows) to eventually end up in pond B or pond C. On leaving a pond, the logs are equ…
Problem
Answer published by the source. Consult the official source to check your work against its answer.
problem
Regions and represent ponds. Logs leave pond and float down flumes (represented by arrows) to eventually end up in pond or pond . On leaving a pond, the logs are equally likely to use any available exit flume. Logs can only float in the direction the arrow is pointing. What is the probability that a log in pond will end up in pond ? Express your answer as a common fraction.
[asy]
label("",(10,22),S);
label("",(10,2),S);
label("",(10,-7),S);
label("",(2,13),S);
label("",(10,12),S);
path a=(10,-10)..(20,0)--(0,0)..cycle;
path b=(10,-7)..(3,0)--(17,0)..cycle;
draw(a);
draw(b);
fill((3.1,0.1)--(16.9,0.1)--(16.9,-0.1)--(3.1,-0.1)--cycle,white);
draw(Circle((10,0),3));
draw(Circle((10,10),3));
draw(Circle((10,20),3));
draw((10,16.9)--(10,13.1),Arrow);
draw((10,6.9)--(10,3.1),Arrow);
draw(Circle((2,10),3));
draw((2,7)--(2.5,0),Arrow);
draw((1.5,7)--(0.2,0),Arrow);
draw((10,16.9)--(2,13.2),Arrow);
draw((10,16.9)--(19.8,0),Arrow);
draw((10,6.9)--(17.2,0),Arrow);
draw((3,8)--(10,3.1),Arrow);
[/asy]
Plain-text mathematical notation (without MathML)
Regions A,B,C,J and K represent ponds. Logs leave pond A and float down flumes (represented by arrows) to eventually end up in pond B or pond C. On leaving a pond, the logs are equally likely to use any available exit flume. Logs can only float in the direction the arrow is pointing. What is the probability that a log in pond A will end up in pond B? Express your answer as a common fraction.
[asy]
label("A",(10,22),S);
label("B",(10,2),S);
label("C",(10,-7),S);
label("J",(2,13),S);
label("K",(10,12),S);
path a=(10,-10)..(20,0)--(0,0)..cycle;
path b=(10,-7)..(3,0)--(17,0)..cycle;
draw(a);
draw(b);
fill((3.1,0.1)--(16.9,0.1)--(16.9,-0.1)--(3.1,-0.1)--cycle,white);
draw(Circle((10,0),3));
draw(Circle((10,10),3));
draw(Circle((10,20),3));
draw((10,16.9)--(10,13.1),Arrow);
draw((10,6.9)--(10,3.1),Arrow);
draw(Circle((2,10),3));
draw((2,7)--(2.5,0),Arrow);
draw((1.5,7)--(0.2,0),Arrow);
draw((10,16.9)--(2,13.2),Arrow);
draw((10,16.9)--(19.8,0),Arrow);
draw((10,6.9)--(17.2,0),Arrow);
draw((3,8)--(10,3.1),Arrow);
[/asy]Original LaTeX notation
Regions $A, B, C, J$ and $K$ represent ponds. Logs leave pond $A$ and float down flumes (represented by arrows) to eventually end up in pond $B$ or pond $C$. On leaving a pond, the logs are equally likely to use any available exit flume. Logs can only float in the direction the arrow is pointing. What is the probability that a log in pond $A$ will end up in pond $B$? Express your answer as a common fraction.
[asy]
label("$A$",(10,22),S);
label("$B$",(10,2),S);
label("$C$",(10,-7),S);
label("$J$",(2,13),S);
label("$K$",(10,12),S);
path a=(10,-10)..(20,0)--(0,0)..cycle;
path b=(10,-7)..(3,0)--(17,0)..cycle;
draw(a);
draw(b);
fill((3.1,0.1)--(16.9,0.1)--(16.9,-0.1)--(3.1,-0.1)--cycle,white);
draw(Circle((10,0),3));
draw(Circle((10,10),3));
draw(Circle((10,20),3));
draw((10,16.9)--(10,13.1),Arrow);
draw((10,6.9)--(10,3.1),Arrow);
draw(Circle((2,10),3));
draw((2,7)--(2.5,0),Arrow);
draw((1.5,7)--(0.2,0),Arrow);
draw((10,16.9)--(2,13.2),Arrow);
draw((10,16.9)--(19.8,0),Arrow);
draw((10,6.9)--(17.2,0),Arrow);
draw((3,8)--(10,3.1),Arrow);
[/asy]level
Level 4
type
Counting & Probability
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