Question

_+_+_=30
fill the boxes using
(1,3,5,7,9,11,13,15)

Answer 1

We wont get a even number if we add odd numbers an odd number of times. 

So this has to be solved using factorial-

3! + 11 + 13 = 30.This will be a solution.

Answer 2

Here you go!
3! + 11 + 13 = 30
We won't get 30 if we add them normally, So using the factorial method. You will get the answer :).