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== Problem 3 ==
== Problem ==


Suppose [<math>a</math> <math>b</math>] denotes the average of <math>a</math> and <math>b</math>, and {<math>a</math> <math>b</math> <math>c</math>} denotes the average of <math>a</math>, <math>b</math>, and <math>c</math>. What is {{1 1 0} [0 1] 0}?
Suppose [<math>a</math> <math>b</math>] denotes the average of <math>a</math> and <math>b</math>, and {<math>a</math> <math>b</math> <math>c</math>} denotes the average of <math>a</math>, <math>b</math>, and <math>c</math>. What is <math>\{\{\text{1 1 0}\} \text{ [0 1] } 0\}?</math>


<math> \textbf{(A)}\ \frac{2}{9} \qquad\textbf{(B)}\ \frac{5}{18} \qquad\textbf{(C)}\ \frac{1}{3} \qquad\textbf{(D)}\ \frac{7}{18} \qquad\textbf{(E)}\ \frac{2}{3} </math>
<math> \textbf{(A)}\ \frac{2}{9} \qquad\textbf{(B)}\ \frac{5}{18} \qquad\textbf{(C)}\ \frac{1}{3} \qquad\textbf{(D)}\ \frac{7}{18} \qquad\textbf{(E)}\ \frac{2}{3} </math>


=== Solution ===
== Solution ==


Average <math>1</math>, <math>1</math>, and <math>0</math> to get <math>\frac23</math>. Average <math>0</math>, and <math>1</math>, to get <math>\frac12</math>. Average <math>\frac23</math>, <math>\frac12</math>, and <math>0</math>. to get <math>\boxed{\textbf{(D)}\ \frac7{18}}</math>
Average <math>1</math>, <math>1</math>, and <math>0</math> to get <math>\frac23</math>. Average <math>0</math>, and <math>1</math>, to get <math>\frac12</math>. Average <math>\frac23</math>, <math>\frac12</math>, and <math>0</math>. to get <math>\boxed{\textbf{(D)}\ \frac7{18}}</math>
==Video Solution==
https://youtu.be/JKO9YzQULvM
~savannahsolver
== See Also ==
{{AMC10 box|year=2011|ab=A|num-b=2|num-a=4}}
{{MAA Notice}}

Latest revision as of 14:48, 16 January 2021

Problem

Suppose [$a$ $b$] denotes the average of $a$ and $b$, and {$a$ $b$ $c$} denotes the average of $a$, $b$, and $c$. What is $\{\{\text{1 1 0}\} \text{ [0 1] } 0\}?$

$\textbf{(A)}\ \frac{2}{9} \qquad\textbf{(B)}\ \frac{5}{18} \qquad\textbf{(C)}\ \frac{1}{3} \qquad\textbf{(D)}\ \frac{7}{18} \qquad\textbf{(E)}\ \frac{2}{3}$

Solution

Average $1$, $1$, and $0$ to get $\frac23$. Average $0$, and $1$, to get $\frac12$. Average $\frac23$, $\frac12$, and $0$. to get $\boxed{\textbf{(D)}\ \frac7{18}}$

Video Solution

https://youtu.be/JKO9YzQULvM

~savannahsolver

See Also

2011 AMC 10A (ProblemsAnswer KeyResources)
Preceded by
Problem 2
Followed by
Problem 4
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 10 Problems and Solutions

These problems are copyrighted © by the Mathematical Association of America.