The average (arithmetic mean) of 11 numbers is 10. When one number is eliminated, the average of the remaining numbers is 9.3. What is the eliminated number?
A. 14
B. 15
C. 16
D. 17
E. 18
[spoiler]OA=D[/spoiler]
Source: Manhattan GMAT
The average (arithmetic mean) of 11 numbers is 10. When one number is eliminated, the average of the remaining numbers
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We know that if mean of \(n\) numbers is \(M\) , then sum of the numbers is \(n\ \cdot\ M\)
So, sum of the 11 numbers is \(11\ \cdot\ 10\ =\ 110\)
After removing one number, sum of remaining numbers is \(9.3\ \cdot\ 10\ =\ 93\)
So the removed number is \(110\ -\ 93\ =\ 17\) D
So, sum of the 11 numbers is \(11\ \cdot\ 10\ =\ 110\)
After removing one number, sum of remaining numbers is \(9.3\ \cdot\ 10\ =\ 93\)
So the removed number is \(110\ -\ 93\ =\ 17\) D