Difference between revisions of "2011 AMC 10B Problems/Problem 2"
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| − | ==Problem== | + | == Problem 2 == |
| − | Josanna's test scores to date are 90, 80, 70, 60, and 85. Her goal is to raise | + | Josanna's test scores to date are <math>90, 80, 70, 60,</math> and <math>85</math>. Her goal is to raise here test average at least <math>3</math> points with her next test. What is the minimum test score she would need to accomplish this goal? |
| − | (A) 80 | + | <math> \textbf{(A)}\ 80 \qquad\textbf{(B)}\ 82 \qquad\textbf{(C)}\ 85 \qquad\textbf{(D)}\ 90 \qquad\textbf{(E)}\ 95 </math> |
==Solution== | ==Solution== | ||
| − | The average of her current scores is 77. To raise it 3 points, she needs an average of 80, and so after her 6 tests, a sum of 480. Her current sum is 385, so she needs a 480 - 385 = 95 (E). | + | The average of her current scores is <math>77</math>. To raise it <math>3</math> points, she needs an average of <math>80</math>, and so after her <math>6</math> tests, a sum of <math>480</math>. Her current sum is <math>385</math>, so she needs a <math>480 - 385 = \boxed{95 \textbf{(E)}}</math>. |
Revision as of 18:57, 25 May 2011
Problem 2
Josanna's test scores to date are 
and 
. Her goal is to raise here test average at least 
points with her next test. What is the minimum test score she would need to accomplish this goal?
Solution
The average of her current scores is 
. To raise it points, she needs an average of 
, and so after her 
tests, a sum of 
. Her current sum is 
, so she needs a 
.
