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Question
The mean of 5 numbers is 18. If one number is excluded, their mean is 16. Find the excluded number.
Solution
The mean of 5 numbers is 18
Then, the sum of 5 numbers = 5×18= 90
If the one number is excluded
Then, the mean of 4 numbers = 16.
∴ Sum of 4 numbers 4 ×16 = 64
Excluded number = 90-64 = 26
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