Add the following numbers and find the answer?

Question

Sum the $3$ numbers from the list

$?+?+?=30$ Fill the boxes using $1,3,5,7,9,11,13,15$

You can also repeat the numbers

Answer 1

It's actually impossible since all numbers are odd and $30$ is even.

Notice that every odd number can be represented as $2n+1$. Thus $$(2n+1)+(2k+1)+(2t+1)=2·(n+k+t+1)+1$$ which is odd and not even

Answer 2

I don't think there is a way to get $30$ using the numbers from that list because all those numbers are odd. We know that odd + odd = even (that's the sum of any two numbers from the list) and even + odd = odd (we add one more number from the list to the sum which is even). So, the sum is always going to be odd, but $30$ is even!