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Question
The mean of 5 numbers is 18. If one number is excluded, the mean of the remaining number becomes 16. Find the excluded number.
Solution
Given the mean of 5 numbers is 18
The total sum of 5 numbers
= 18 x 5
= 90
On excluding an observation, the mean of remaining 4 observation is 16
= 16 x 4
= 64
Therefore the sum of the remaining 4 observations
total of 5 observations-total of 4 observations
= 90 - 64
= 26.
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