I'm not going to help a rude classmate pass a hard exam
Why won't you help them?
They were rude to me before so I don't want to help them.
You should help this classmate. Sure, they may be rude, but they need help and you could become friends.
I don't care. That's ridiculous.
Denying them your time could save you time for other school work you may have. I think it is important to focus on your own education and make sure you pass.