Find all sets of three consecutive odd integers whose sum is between 20 and 30

3 odd numbers sum between 20 & 30

you get n + n+2+n+4 = between 20 & 30

3n+6 = between 20 & 30

subtract 6 from all 3 numbers you now have 3n = between 14 and 24

divide all 3 by 3 to get n = between 14/3 and 8

14/3 = 4 2/3

the only odd numbers between 4 2/3 and 8 are 5 & 7

so you have 5 + (5+2) + (5+4) = 21

and 7 + (7+2) + (7+4) = 27

5, 7, 9; 21

7, 9, 11; 27

5, 9, 13? 27