Difficulty: Easy
Correct Answer: 409
Explanation:
Introduction / Context:Finding the mean of a finite set is a direct total divided by count operation. Careful addition avoids arithmetic slips.Given Data / Assumptions:
Concept / Approach:Sum all values accurately, then divide by 9.Step-by-Step Solution:
Partial sums: 253 + 124 = 377377 + 255 = 632632 + 534 = 11661166 + 836 = 20022002 + 375 = 23772377 + 101 = 24782478 + 443 = 29212921 + 760 = 3681Average = 3681 / 9 = 409Verification / Alternative check:Use grouping to cross check: (253 + 443) + (124 + 836) + (255 + 375) + 534 + 101 + 760 = 696 + 960 + 630 + 534 + 101 + 760 = 3681; 3681/9 = 409.Why Other Options Are Wrong:
Common Pitfalls:Arithmetic errors when summing many numbers; double count or omission mistakes.Final Answer:
409
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