Problem-Solving and Data AnalysisMediumMean from percentages of a group
Problem-Solving and Data Analysis practice question
In a class, 40% of the students scored 60 on a test and the remaining 60% scored 85. What is the mean score for the class?
Answer: 75
Weight each score by its share: 0.40 × 60 + 0.60 × 85 = 24 + 51 = 75.
Common wrong answers
- If you answered 70
- 70 weights the scores the wrong way round (0.6 × 60 + 0.4 × 85).
- If you answered 145
- 145 is 60 + 85, the two scores added with no weighting.
- If you answered 72.5
- 72.5 is the plain average of 60 and 85, ignoring that more students scored 85.
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