I see that you're learning Spanish. "Co" and "jaki" work the exact same way as the Spanish "qué" and "cuál".
In Spanish, "qué" would imply that you want a definition. Let's say you don't know what a dog is, so you would ask "¿qué es un perro?" (what is a dog?) because you want a definition. This is when you would use "co" in Polish.
In Spanish, "cuál" would imply that you want general information. So, let's just say you are talking to someone you like and you want to get their number, you would ask "¿cuál es tu número?" (what is your number?). Here, you know what a [phone] number is and aren't asking for a definition. This is when you would use "jaki" in Polish.
I'm on the fence. Yes, it would work in this context, but we don't know the context and it's better to not make people think that "wynik" means "answer"... Besides, if it was about maths it would most probably be "Jaki jest wynik?" (you're expected to get the correct result), and if those were classmates discussing a hard maths task and the results they got, I'd ask "Ile ci wyszło?".