SOLUTION: When 15 is appended to a list of integers, the mean is increased by 2. When 1 is appended to the enlarged list, the mean of the enlarged list is decreased by 1. How many integers w
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-> SOLUTION: When 15 is appended to a list of integers, the mean is increased by 2. When 1 is appended to the enlarged list, the mean of the enlarged list is decreased by 1. How many integers w
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Question 1067722: When 15 is appended to a list of integers, the mean is increased by 2. When 1 is appended to the enlarged list, the mean of the enlarged list is decreased by 1. How many integers were in the original list? Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website! Let = the number of integers in the original list
Let = the mean of the original list
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Originally, the total, , of the integers was:
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Add to the list
(1)
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Add to the enlarged list
(2)
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(1)
(1)
(1)
and
(2)
(2)
(2)
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Multiply both sides of (2) by
and subtract (1) from (2)
(2)
(1)
------------------------
and
(1)
(1)
(1)
(1)
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There were 4 integers in the original list
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check:
(1)
(1)
(1)
--------------------
(1)
(1)
(1)
(1)
and
(2)
(2)
(2)
(2)
OK
