SOLUTION: the mean of a set of numbers is 120. if one number is increases by 300, the mean increases to 135. how many numbers are in the set?

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Question 359452: the mean of a set of numbers is 120. if one number is increases by 300, the mean increases to 135. how many numbers are in the set?
Answer by edjones(8007)   (Show Source): You can put this solution on YOUR website!
Let x=numbers in the set.
(120(x-1)+420)/x=135
(120x-120+420)/x=135
(120x+300)/x=135
120x+300=135x
15x=300
x=20 numbers in the set.
.
Ed

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