Question 1055624
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+2}}}= the second one of the 3 consecutive odd numbers
{{{n+4}}}= the third one of the 3 consecutive odd numbers
{{{(n+(n+2)+(n+4))/3=39}}} is the average of the 3 consecutive odd numbers.
Solving that equation, we get
{{{(n+(n+2)+(n+4))/3=39}}}
{{{(n+n+2+n+4)/3=39}}}
{{{(3n+6)/3=39}}}
{{{3n+6=39*3}}}
{{{3n+6=117}}}
{{{3n=117-6}}}
{{{3n=111}}}
{{{n=111/3}}}
{{{n=37}}}
So, the second of 3 consecutive odd numbers is {{{37+2=39}}} ,
and the sum of the first 2 numbers is
{{{37+39=highlight(76)}}}