Civil Service Exam Reviewer · Averages · hard
The average of 9 numbers is 23. The average of the first 5 is 24, and the average of the last 5 is 25. What is the middle (5th) number?
- 23
- 25
- 38
- 43
Answer
C. 38
Solution
First 5 sum = 120; last 5 sum = 125. Together they count the middle number twice: 245 − 207 = 38.
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