How long should it take for a kitty to use the litterbox and eat food?

Welcome back!

We got a new kitty last night from a friend of my mom, and she said the cat used to eat a lot and was litterbox trained. She wont touch the food and wont go in the litterbox. She is only 5 months old and is used to being around cats, so i think she may need to feel comfortable around the family, but i want another opinion. any help is appreciated.