Quiz time.

The Red Sox led the A.L. East by 3½ games with 11 to play after last night’s action. The last time they blew a lead that big in that span of time, who was president? What was the average price of a gallon of gasoline? The average price of a house? What did a loaf of bread cost?

Give up?

You should. They’re trick questions.

The Red Sox have never blown a lead as big as 3½ games with 11 games left in a season. They’ve never blown a lead half as big. In fact, since the major-league schedule was expanded to 162 games, only once have the Sox been in first place with 11 games left and not finished first. That was in 1972 — and even then, they were only tied for first.

To find a year in which the Sox were in first place with 11 games and didn’t finish first, you have to go all the way back to 1948. At that, they led by only one-half game. And, beyond that, they actually finished the regular season tied for first, but lost a one-game playoff to the Cleveland Indians.

(In 2005, the Sox were in first by one-half game over the Yankees and finished tied with New York. Because the Yankees won the season series, they were awarded the A.L. East title and the Sox received the wild-card.)

The point of all this is simple: When the Red Sox beat the Yankees on Saturday afternoon, they put themselves in a position where they’re all but assured of finishing first. That victory meant the Yanks could be no closer than 4½ back when they left town Sunday night, and, with 12 games remaining, that’s an almost insurmountable deficit.

Almost. Baseball fans of a certain age all remember the 1964 Philadelphia Phillies, the Pholdin’ Phils. They led by 6 ½ with 12 to play but, thanks to a 10-game losing streak, wound up finishing second. It was one of the most historic collapses in baseball history.

But that’s what it would take for the Sox to lose now: An historic collapse. (Not to mention a two-week hot streak by the Yankees, who have used up almost all their margin of error and need to win almost every game from here on in to catch Boston.) The type of collapse that just hasn’t happened in Red Sox history.

In 1995, it was almost impossible for them to lose the division — they had a 10½-game lead with 12 to play — and the impossible didn’t happen.

When they were ahead by five games in 1988, they closed the deal and won the division.

Ditto in 1986, when they had a 9½-game lead with 12 to play.

And 1975, when they led by the same 4½-game margin they had prior to last night and wound up winning by 4½.

There were other years when they weren’t in first with 12 to go, and still won. Like 1990, when they trailed by one game. And 1967, when they also trailed by one.

All of this, of course, means nothing when it comes to the postseason. The season begins anew on Oct. 3, and it takes a different set of muscles to win three short playoff series. Sox fans, aware their team lost 8 of its last 10 meetings with the Yankees this season, are concerned about playing New York in the ALCS. And with reason. The Sox don’t appear to have enough left-handed pitching to negate New York’s left-handed power, and the veteran Yankee pitchers — not the pretenders the injury-riddled Yanks were parading out in April and May — have had success shutting down Boston’s offense this season.

But that’s another worry.

Worries about finishing first in the division should be over.

amartone@projo.com