Well I'd have to say that just by looking at it, 0 is a solution:
Also 1 is a solution since all those numbers add to 24:
However, beyond that, I do not know. There might be more than 2 solutions, but maybe whoever gave you this problem didn't think of that. I'd say look at the solutions of 1 and 0 if you have a problem like this, and go from there. In my opinion this looks like a thinking problem, something you're just suppose to see.