Math Help - Arithmetic Mean

1. Arithmetic Mean

The arithmetic mean of nine numbers is 54. Of two number u and v are added to the list the mean of the eleven numer list becomes 66. what are the values of u and v?

2. Originally Posted by Dragon
The arithmetic mean of nine numbers is 54. Of two number u and v are added to the list the mean of the eleven numer list becomes 66. what are the values of u and v?
Hello, Dragon,

the sum of the first nine numbers is: 9 * 54 = 486.

So your problem becomes:

$\frac{9*54+u+v}{11}=66$

That means: u + v = 240

or: u = 240 - v

So you can construct a pair of numbers with this property.

EB