The mean of a set of 12 numbers is 24. If one item is excluded, the mean gets…
2023
The mean of a set of 12 numbers is 24. If one item is excluded, the mean gets reduced by 3. What is the excluded number?
- A.
45
- B.
62
- C.
57
- D.
55
Attempted by 129 students.
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Correct answer: C
Solution:
Compute the total sum using the mean of 12 numbers: total sum = 12 × 24 = 288.
After excluding one item the mean reduces by 3, so the new mean = 24 − 3 = 21. Sum of the remaining 11 numbers = 11 × 21 = 231.
The excluded number = original total − remaining total = 288 − 231 = 57.
Answer: 57