What does an average 3 or 4 day trip credit?

May 3rd Class
 

5 hrs/day minimum day.

Depends on the trip.
Early shows with late finishes will trigger the trip rig.
1 for 3.5
One hour pay for each 3.5 hours time away from base.
So for a 4 day with 75 hours away from base will pay 21:25.

So it depends.

My experience EWR 73 average is 5-6.5 hrs/day. I've had 19 hour 3 days and 27 hour 4 days. I've also had more than a few 15 and 20 hour 3/4 days.