# Thread: Sleepless nights. Pls help me

1. ## Sleepless nights. Pls help me

Construct a formal proof following;
If he recieved the wire, then he took the plane and if he took the plane he will not be late for the meeting. If the telegraph was incorrectly addressed, then he will be late for the meeting. He recieved the wire or the telegraph was incorrectly addressed therefore, he took the plane or he will be late for the meeting.

2. ## Re: Sleepless nights. Pls help me

Denote individual propositions by letters (preferably in a mnemonic way) and write the assumptions symbolically.

Which proof system do you need to use? See this thread.