I have 2 questions im new at odds.

A girl have 8 friends and she want to invite 5 of them to her house.How many choices have if 2 of her friends are quarreled and can't invite both of them in her house?

And the other:

We have 10 people and we want put them in 10 seatmate chairs but 2 of them must have difference 3 chairs.How much choices we have to put them?

Thank you.

Dimitristhym Oct 13, 2019