Q8 of 71 Page 199

The mean of five numbers is 18. If one number is excluded the mean becomes 16. Find the excluded number.

We know that,


Where, Mean, xi = observations and n = no. of observations.


Let the excluded no. be x and sum of other numbers be S




⇒ S + x = 90……… (1)


Also,



⇒ S = 64


Substituting value of S in (1), we get -


64 + x = 90


⇒ x = 26


∴ excluded number = 26


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