Ok NFHS rules.

On a passing play there's a late hit on the QB and a late hit out of bounds. Are both penaltes enforced against B (total 30 yards)?

On a separate play, A is guilty of illegal motion, but B has a late hit on the QB. Do these still offset?

And last, A is guilty of illegal motion, but B hits the quarterback late and inferferes with the receiver. All of it offsets?

Thanks for your help.

We can't tell because you're a little loose with your terminology. By late hit on the QB do you mean a live ball roughing the passer call or a dead ball personal foul?

not a dead ball hit. QB was hit after the throw, during the play. The receiver was hit late after running OOB.

On the passing play, you have a live-ball RTP, and a dead-ball PF. Both will be enforced.

On the separate play, you have live-ball fouls by both teams. They offset and the down is repeated.

And last, you have live-ball fouls by both teams even though there were more by one than the other. Offset and repeat.

Just make sure you call it "roughing the passer," same as in the rulebook.

1. Roughing the passer and late hit OOB. Enforce the RTP first, 15 yards from the last run and an automatic first down; then enforce the dead ball personal foul (it occured after the play was over). The total will be 30 yards from the dead ball spot (assuming neither is half-the-distance). Note the special enforcement for RTP (from the end of the run).

2. Illegal motion by A and RTP by B. Double foul, replay down.

3. Illegal motion by A, RTP by B, pass interference by B. Double foul, replay down.