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The arithmetic mean of nine numbers is 54. If two numbers $u$ and $v$ are added to the list, the mean of the eleven-member list becomes 66. What is the mean of $u$ and $v$?

 Jan 18, 2020
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54 * 9 = 486

 

(486 + u+v)/11 =66

486 + u + v = 726

u+v = 240

 

240/2 =120

 Jan 18, 2020

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