The plan to wipe the extra 240 km from the odometer by driving in reverse presents us with a serious plot hole.

34 individual hand signals. But as fascinating as this sounds, research puts the maximum teenage attention span at 20 minutes, so by 11:20am they’d have had enough of hand-tohand capitalism and started thinking about lunch. Time for a fancy French restaurant somewhere north of the city.

12:00pm Chez Quis

No self-respecting fine-dining establishment would serve meals before midday, so we can’t feed our trio any earlier than 12:00pm. That gives them 40 minutes to make their way to the lunch spot – Chez Quis. This was never a real restaurant, but nonetheless a real location only 3.54 km from the Chicago Board of Trade. These 40 minutes are covered via a leisurely 5.31 km/h stroll from the Chicago Board, burning a respectable 200 calories (837 kj) each in the process. This means our teen heroes could arrive bang on 12:00pm, with big appetites and primed to steal a booking from Abe Froman, “Sausage King of Chicago”. The morning timeline fits perfectly. Now for the afternoon.

1:25pm Wrigley Field

After lunch we find our truants off to a game of baseball at Chicago’s iconic Wrigley Field. Day games during the 1980s didn’t start until 1:25pm and a trip from the restaurant to the stadium would only take 15 minutes in the early afternoon. This allows 70 minutes for lunch, easily accommodating the 600 chews required for starters, mains and desserts – 55 mouthfuls, 13 chews per mouthful. Splendid! Now to the ball game.

A whole game usually takes three hours, which would blow out our entire timeline. However, during a scene in a downtown bar, a game is playing on TV when a sportscaster announces: “Runner on first base, nobody out. That’s the first hit they’ve had since the fifth inning…” This is followed by Ferris catching a foul ball. Eureka! Their game has already had at least five innings. If an innings takes 20 minutes on average, then we can estimate that they have been there at least 100 minutes. If we throw in just half of the sixth innings, then the whole time at the stadium amounts to 110 minutes. Given that at Wrigley Field there are approximately 17,000 seats in range of a foul ball and each person could cover an area of nine seats (their seat + one seat in every direction), it puts the odds at 1 in 1,889. With the average game producing 15 foul balls by the fifth inning, Ferris had a 1 in 126 chance of catching at least one foul ball… But the main prize is the 6pm deadline and there’s a lot to pack in before then.

3:25pm Art Institute

Leaving Wrigley Field by cab at 3:15pm gets us to The Art Institute of Chicago in 10 minutes. Inside the gallery we only have time for a whirlwind tour of modern art – 15 minutes tops. This has them out on the street by 3:40pm and only a short walk from a German-american Parade taking place a few blocks away.

3:50pm Twist and Shout

We can place Cameron and Sloane at a public art piece known as Calder’s Flamingo just before they discover Ferris on a parade float. This is situated only five minutes by foot from the art museum. However, in the film they are stuck in a cab… eek! Walk, you lazy fools! We can allow 10 minutes in the cab before Ferris ascends a float to become king for a day. However, this life-changing moment must be over in 25 minutes. That’s all. Sorry, folks. We’re running out of time.

4:50pm Glencoe Beach

Calder’s Flamingo is 580 m from the parking garage – the same distance that the parking garage was from Willis Tower! Unfortunately, numerical symmetry isn’t proof for meeting the 6pm deadline, so we must keep calculating. Another 5-minute walk has us back in the Ferrari by 4:20pm. Then it’s a 30-minute drive to their next location, Glencoe Beach, where each of the Ferrari’s wheels rotate 8250 times to cover the required 38.3 km. It’s only a small addition to the 240 km – or 51,720 wheel rotations – already accumulated by the carpark attendants’ joyride that our trio has just discovered.

This realisation induces the catatonic episode in Cameron, during which his blink rate dropped from 12-15 blinks/min down to zero. Here, we can only allow 10 minutes.

5:05pm Some random jacuzzi

Next we see Ferris and Sloane relaxing in a jacuzzi trying to motivate an unresponsive Cameron to join them. This location isn’t given any context in the film and our timeline is getting super tight! Let’s give

them 5 minutes to get there and 15 minutes in the water. However, the scene is problematic, as a three-person 1,000L jacuzzi can, at best, heat up at a rate of 3˚C per hour. In 15 minutes that’s a measly 0.75˚C. Perhaps the offer of a cold jacuzzi was enough to keep Cameron out of the water? Luckily for us there isn’t time to worry about it too much since we need to get back to Cameron’s house – at most five minutes away.

5:25pm Cameron’s house

Finally we have arrived at the climactic scene: a vintage Ferrari jacked up and humming in reverse. If we get to Cameron’s garage by 5:25pm we only have 30 minutes left in the budget for the Ferrari’s destruction. Yet their plan to wipe the extra 240 km from the odometer by driving in reverse presents us with a serious, possibly terminal, plot hole. The Ferrari’s factory specs have the reverse gear ratio at 13.5 and the redline rpm at 6,500 which, when combined, means their car had a top speed of 61 km/h in reverse. This means for their plan to work they would have needed at least 3 hours and 56 minutes. Luckily we are saved from this mathematical howler by the Ferrari launching backwards through a glass wall. Phew. Time to bring it home.

5:55pm Sloane’s watch

When Ferris says goodbye to Sloane he looks at her watch. It’s 5:55pm. Only five minutes to get home before his parents. This final scene really needs its own detailed analysis, but having been thoroughly entertained up to this point, I am happy to accept that it was achievable. But more importantly, everything leading up to 5:55pm, excluding some minor mathematical indiscretions, was also achievable. Which, I have to admit, comes as a big surprise.

Yet perhaps it was to be expected. Hughes’ masterpiece was set in a city he understood innately. Like a London cabbie he had a mental map of each location when writing and editing his film. And within those constraints he crafted a brilliant story of mid-’80s teenage rebellion. And we’re glad he did, because there is no way anyone could pull a Ferris Bueller’s day off today. The Ferrari would have its own tracking device. The French restaurant would have image-searched “Chicago Sausage King” to verify Ferris’ claim. And social media would have exploded during Twist and Shout. And that would be it. Ferris Bueller’s day over! But instead we have a rite of passage for any teen wondering what life would be like if they could stop and look around once in a while… and the opportunity for a nerd like me to overanalyse the whole thing on a spreadsheet.

Thank you, Ferris Bueller, you’re still my hero.

SIMON PAMPENA is a journalist, presenter and Australian Numeracy Ambassador.