SOLUTION: the average of a set of numbers is 23. When -35 is added to the set, the average is 21. How many numbers were in the original set?

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Question 1102700: the average of a set of numbers is 23. When -35 is added to the set, the average is 21. How many numbers were in the original set?
Answer by ikleyn(52852)   (Show Source): You can put this solution on YOUR website!
.
The condition in the Math form says THIS


23*n - 35 = 21*(n+1).


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23n - 35 = 21n + 21  ====>  2n = 21 + 35 = 56  ====>  n =  = 28.

Answer. n = 28.



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