$\square+\square+\square=30$, with boxes filled using $1, 3, 5, 7, 9, 11, 13, 15$, possibly repeated. How? From the days I started to learn Maths, I've have been taught that 

Adding Odd times Odd numbers the Answer always would be Odd; e.g., 
  $$3 + 5 + 1 = 9$$

OK, but look at this question 

This question was solved and the answer was 30, how it was possible? Need a valid explanation please.

If this is a riddle, I would do : 13,1 + 7,9 + 9
