SOLUTION: The mean of five numbers is 6. If one of the numbers is removed, the mean becomes 7. What is the value of the number that was removed?

Question 316008: The mean of five numbers is 6. If one of the numbers is removed, the mean becomes 7. What is the value of the number that was removed?
Answer by Edwin McCravy(20054) (Show Source): You can put this solution on YOUR website!
The mean of five numbers is 6. If one of the numbers is removed, the mean becomes 7. What is the value of the number that was removed?








Let R = the number that was removed.

Then the new Sum after removing R was 30-R

Going back to











So 2 was removed.

---------------------

Suppose the 5 numbers were 2, 5, 6, 8, 9

Their mean is 

If we remove the 2, the numbers left are 5, 6, 8, 9

Their mean is 

So we know we are right that 2 was removed.

Edwin

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