A Little Rusty

[LeRoy]

Ball at the 50 yard line. A throws a pass which is intercepted at the 30 yard line by B. And now A is running up the field after the interception and has a Block in the Back at the 31 yard line. As the runner is tackled on the 40 yard line we have a 15 yard facemask. What is the penalty enforcement? and where is the ball put in play next.

[bisonlj]

B must decline A's foul to retain the ball. Otherwise it will be a double foul and the down replayed. B's foul happened behind the end of the run so this is the enforcement spot. B's ball 1st and at the B21.

[LeRoy]

That's what I thought ... Thanks