Self-study
I am stuck. Can anyone help?
An apartment building has five floors. Each floor has either one or two apartment. There are exactly eight apartments in the building. The residents of the building are J,K,M,N,O,P and Q, who each live in a different apartment.
Admin note: edited title
Hello, thank you for the tip, but I am specifically having difficulties with contrapostives and applying that concept to the question itself.