SOLUTION: the mean of six numbers is 10. When another number is added the mean changes to 9. What number is added?

Question 977912: the mean of six numbers is 10. When another number is added the mean changes to 9. What number is added?
Answer by Cromlix(4381) (Show Source): You can put this solution on YOUR website!
Hi there,
If the mean of 6 numbers is 10
then the total was 6 x 10 = 60
When another number is added
then this totals 7 numbers
If the new mean is 9 then the new
total = 63
New total - Old total
63 - 60 = 3
Therefore 3 must have been
the number added.
Hope this helps:-)
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