SOLUTION: The average of 3 consecutive odd numbers is 39. What is the sum of the first 2 numbers?

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Question 1055624: The average of 3 consecutive odd numbers is 39. What is the sum of the first 2 numbers?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
QUICK MENTAL MATH (good for tests like the SAT):
The average for 3 (or 5, or 7, or ...) equally spaced numbers is
the number in the middle.
So, the 3 consecutive odd numbers are 37, 39, and 41.
The sum of the first 2 of those numbers is 37+39=76 .

SHOWING YOUR WORK:
If you have to justify why the average (also called the mean)
of 3 (or 5, or 7, or ...) equally spaced numbers is
the number in the middle of the ordered list
(also called the median),
the written down explanation below works better.
n= the first of the 3 consecutive odd numbers
n%2B2= the second one of the 3 consecutive odd numbers
n%2B4= the third one of the 3 consecutive odd numbers
%28n%2B%28n%2B2%29%2B%28n%2B4%29%29%2F3=39 is the average of the 3 consecutive odd numbers.
Solving that equation, we get
%28n%2B%28n%2B2%29%2B%28n%2B4%29%29%2F3=39
%28n%2Bn%2B2%2Bn%2B4%29%2F3=39
%283n%2B6%29%2F3=39
3n%2B6=39%2A3
3n%2B6=117
3n=117-6
3n=111
n=111%2F3
n=37
So, the second of 3 consecutive odd numbers is 37%2B2=39 ,
and the sum of the first 2 numbers is
37%2B39=highlight%2876%29