Mathematics
NULL
Medium
Question
The mean score of a group is 52. The brightest 20% averaged 80 and the dullest 25% averaged 31. What is the mean of the remaining 55%?
A
45
B
50
C
51.4 approx.
✓ Official correct answer
D
54.6 approx.
Community credibility
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A
45
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B
50
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C
51.4 approx.
No member explanations yet for this option.
D
54.6 approx.
No member explanations yet for this option.
Explanation
0.2×80 + 0.25×31 + 0.55m = 52 ⇒ m ≈ 51.4.