Answer:
The correct answer is : I have to invite 8 friends
Explanation:
Two are married so a friend cannot be invited without the other one. Therefore, I'm going to be invited to a distinct friend instead of those two. The total number of available people is 10. And can be invited only 8 friends now because it will avoid any possible confrontation between the ones who don't like each other.
n=10
r=8
