Difference between revisions of "2007 AMC 8 Problems/Problem 1"

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<math>x = 12</math>
 
<math>x = 12</math>
  
So, the answer is <math>\boxed{D}</math>
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So, the answer is <math> \boxed{\textbf{(D)}\ 12} </math>
  
 
==See Also==
 
==See Also==

Revision as of 12:09, 9 December 2012

Problem

Theresa's parents have agreed to buy her tickets to see her favorite band if she spends an average of $10$ hours per week helping around the house for $6$ weeks. For the first $5$ weeks she helps around the house for $8$, $11$, $7$, $12$ and $10$ hours. How many hours must she work for the final week to earn the tickets?

$\mathrm{(A)}\ 9 \qquad\mathrm{(B)}\ 10 \qquad\mathrm{(C)}\ 11 \qquad\mathrm{(D)}\ 12 \qquad\mathrm{(E)}\ 13$

Solution

Let $x$ be the number of hours she must work for the final week. We are looking for the average, so $\frac{8 + 11 + 7 + 12 + 10 + x}{6} = 10$

Solving gives:

$\frac{48 + x}{6} = 10$

$48 + x = 60$

$x = 12$

So, the answer is $\boxed{\textbf{(D)}\ 12}$

See Also

2007 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
First Problem
Followed by
Problem 2
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 AJHSME/AMC 8 Problems and Solutions