penalty mark placement

[wwcfoa43]

Canadian Ruling:

First Scenario:
Assuming the ball was at the 38 when the foul occured, the penalty is enforced from there since 1st down yards have been gained. So the result after the 10 yards would be 1st and 10 at the Team A 28 yard line.

Second Scenario:
Assuming the ball was at the 42 yard line when the foul occured then yards were not gained so the penalty is enforced from the PLS (Point of Last Scrimmage) so the result would be 2nd and 30 at the Team A 15 yard line.