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?
#1There are (63)=20(63)=20 possible ways for inviting the two. Also, there are (65)=6(65)=6 ways of not inviting them. Thus, there are 26 possible invitations that satisfy these criteria ((63)+(65)=26(63)+(65)=26) \(26\)
#2 use combinations for this one also