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Mathematics
Averages
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RRB NTPC Graduate Tier 1 2025 Shift-2 📅 06 Jun, 2025

The average of 10 observations is 40. It was realised later that an observation was misread as 34 in place of 43. Find the correct average.

A
39.9
B
43.9
C
41.9
D
40.9
Result Summary
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RRB NTPC Graduate Tier 1
2025 • 06 Jun, 2025 • Shift-2
The average of 10 observations is 40. It was realised later that an observation was misread as 34 in place of 43. Find the correct average.
Correct Answer
40.9
Initial Sum Calculation: The total sum of the 10 observations based on the incorrect average is 10 × 40 = 400.Error Correction: The wrong value included was 34......
Ref/Book : RRB NTPC Graduate Tier 1 2025
Ref. Subject Mathematics
Chapter -
Ref. Topic Averages
Pg. No -
💡 Analysis & Explanation
Initial Sum Calculation ▼
The total sum of the 10 observations based on the incorrect average is 10 × 40 = 400.
Error Correction ▼
The wrong value included was 34, while the correct value should have been 43. The net difference to be added to the sum is (43 - 34) = +9.
Final Evaluation ▼
The corrected total sum becomes 400 + 9 = 409. The new, accurate average is 409 ÷ 10 = 40.9.
Conclusion ▼
The correct average is 40.9.
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