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2015 AMC 10A Problem 5

Problem 5 of 25EasierProbability & Statistics

Mr. Patrick teaches math to 1515 students. He was grading tests and found that when he graded everyone’s test except Payton’s, the average grade for the class was 80.80. After he graded Payton’s test, the class average became 81.81. What was Payton’s score on the test?

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Solution

The total for the first 1414 graded tests was 14⋅80=112014\cdot 80=1120. After Payton’s test was included, the total became 15⋅81=121515\cdot 81=1215. Therefore Payton’s score was 1215−1120=951215-1120=95. Thus, E is the correct answer.
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