Question

1,3,5,7,9,11,13,15?+?+?=30(numbers may be repeated)

Answer 1

When adding odd numbers we do not get an even number .....! - So this possible only through FACTORIAL method...! ⇒ 3!+ 15+9=30

Answer 2

It is imposibble to get an even number by adding  odd numbers it can be done with factorial method that is 
3! + 15 + 9 = 30
3! + 11 + 13 = 30 

Without factorial method it is impossible 

Hope It Helped You