This question already has an answer here:
Note that all the elements of the set are odd.
Hence, even if we repeat, we have, w.l.o.g, the following cases
(i) Odd $x$ + Odd $x$ + Odd $y$ = Even+Odd=Odd
(ii) Odd $x$ + Odd $y$ + Odd $z$ = Odd
(iii) Odd $x$ + Odd $x$ + Odd $x$ = Even+Odd=Odd
…. while $30$ is even.
I actually remember this question which is rumored to be from an IAS exam and no one could solve it except the topper. That’s actually a false rumor.
The only way you can get $30$ is by doing it in a mathematically incorrect way (by a “trick”), like $7.5+9.5+13=30$
Other than that, this question simply is a bogus question.