Problem:
Mr. Patrick teaches math to 15 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 . After he graded Payton's test, the class average became 81 . What was Payton's score on the test?
Answer Choices:
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Solution:
The sum of the 14 test scores was . The sum of all 15 test scores was . Therefore Payton's score was .
OR
To bring the average up to 81 , the total must include 1 more point for each of the 14 students, in addition to 81 points for Payton. Therefore Payton's score was .
The problems on this page are the property of the MAA's American Mathematics Competitions