Difference between revisions of "2011 AMC 12A Problems/Problem 14"

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== Problem ==
 
== Problem ==
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Suppose <math>a</math> and <math>b</math> are single-digit positive integers chosen independently and at random. What is the probability that the point (a,b) lies above the parabola <math>y=ax^2-bx</math>?
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<math>
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\textbf{(A)}\ \frac{11}{81} \qquad
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\textbf{(B)}\ \frac{13}{81} \qquad
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\textbf{(C)}\ \frac{5}{27} \qquad
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\textbf{(D)}\ \frac{17}{81} \qquad
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\textbf{(E)}\ \frac{10}{81} </math>
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== Solution ==
 
== Solution ==
 
== See also ==
 
== See also ==
 
{{AMC12 box|year=2011|num-b=13|num-a=15|ab=A}}
 
{{AMC12 box|year=2011|num-b=13|num-a=15|ab=A}}

Revision as of 01:34, 10 February 2011

Problem

Suppose $a$ and $b$ are single-digit positive integers chosen independently and at random. What is the probability that the point (a,b) lies above the parabola $y=ax^2-bx$?

$\textbf{(A)}\ \frac{11}{81} \qquad \textbf{(B)}\ \frac{13}{81} \qquad \textbf{(C)}\ \frac{5}{27} \qquad \textbf{(D)}\ \frac{17}{81} \qquad \textbf{(E)}\ \frac{10}{81}$

Solution

See also

2011 AMC 12A (ProblemsAnswer KeyResources)
Preceded by
Problem 13
Followed by
Problem 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 12 Problems and Solutions