Question 128214
Three consecutive odd numbers would be
{{{7}}}, {{{9}}}, {{{11}}}
All you do is skip the numbers in 
between, which are even and don't count
The problem wants to know what consecutive
odd numbers add up to {{{39}}}
Call the smallest odd number {{{n}}}
The next higher odd number would then 
be {{{n + 2}}}, and the highest consecutive
odd number would be {{{n + 4}}}
Now add them up
{{{n + n + 2 + n + 4 = 39}}}
{{{3n + 6 = 39}}}
{{{3n = 33}}}
{{{n = 11}}}
{{{n + 2 = 13}}}
{{{n + 4 = 15}}}
The consecutive odd numbers that add up to 39
are 11, 13, and 15
check:
{{{11 + 13 + 15 = 39}}}
{{{39 = 39}}}
OK