The Royal Society of Chemistry has announced the winner of a competition to solve the conundrum at the end of the iconic UK film The Italian Job.
In the film, the gold is smuggled out of Turin in Mini Coopers before being loaded onto the bus
In the film, the robbers' coach almost drives off a cliff, ending up balanced precariously on the edge, with the gang at one end and their gold at the other.
The RSC asked for ideas to get the gold off the coach before it tips over. John Godwin from Surrey came up with the winning idea, which involves draining fuel from the vehicle.
Read more about the winning idea
BBC News website readers have sent their comments about the winning idea -and some even had a go at trying to solve the problem and get the gold.
So... once they've deflated the tyres and drained the fuel tanks (presumably over the edge of the cliff) how do they drive away with the gold? The winning solution has just replaced one problem with another.
Mark Crossland, Exmouth
But if they empty the fuel, how will they get away?
Are we sure that the fuel tank is at the rear on this type of coach ?
The maths sounds feasible, but what about the time factor? A passing police car, or worse, the Mafia (who warned them about getting caught), would be out looking for the coach, and this operation would take a few hours. Also, assuming the coach is rear-wheel drive, the gold would have to be unloaded because the coach could not be driven - its rear wheels were overhanging. Anyone for hitch-hiking?
Ray Milner, Hunmanby
Why bother draining the fuel? Indeed, how would you even get to the tank to drain it? Besides, once you've managed to get one man out of the bus the problem is essentially solved, since he can then load up rocks to his heart's content and stabilise the bus enough to start moving the gold. Once the gold starts moving the situation gets easier and easier.
Pretty smart. However, how do they knock out the windows at the rear without adding weight to the rear half of the coach - how do they lower someone out of the windows to deflate the rear tyres without doing the same - where is the panel giving access to the fuel tank and how can it be emptied from inside? If it's at the back the same problem exists: if not, then it might not reduce the weight at the rear. Great competition idea - how about one of the gold bars as a prize!
And how exactly do you drain the fuel from the bus if the fuel tank is at the back, which is hanging over the edge?
Michael Caine said on a chat show years ago that this winning idea would have been the solution had the planned sequel been made. I doubt they used as much maths though.
If my memory of the film serves me correctly, the accident happened during the middle of the day. This means the chances are that they would have been aprehended by the authorities long before they executed such a cunning plan!
Mandy Friend, Canterbury
I remember doing O level physics just to find out but my class never worked it out and our teacher always said, 'You work it out'. I seem to remember we couldn't resolve whether Michael Caine and the others should stand up or sit down...
Katy Charles, London
Get off the coach, push it over, collect the gold from the wreck later.
Tom Levins, Gerrards Cross
Surely it makes sense to run the engine until the fuel in the tank at the rear is reduced by around 75kg (the weight of a single bank robber) then a person can go to the back of the bus and start moving the gold to the front. Easy. And, if your really bothered about the counterweight situation you get everyone else in the bus to climb in to the cab of the bus.
Everyone - even Charlie - gets right to the front of the coach. The heaviest sits on the steering-wheel. The lightest (probably Robert Powell) leans out and picks up a small boulder, placing it carefully near the front. Then a second, larger one, then a third until more than one person can do the boulder-collection. Eventually someone can leave the coach to get really big boulders, after which it's easy.
Tat Wood, Leytonstone
One by one all the men move to a point whereby they can leave the bus which will rock it back towards the road. They leave the bus one by one, each going outside and holding the bus on its balance. Once all are out, you drop the bus over the edge of the cliff. As gold only melts at 1064 degrees Celsius the boys could get to the bottom of the mountain, where they had come from and retrieve the gold from the burnt out wreck. The gold would still be in its normal state.
Ben Cooper, Selsey
Move all the people to the end of the bus on the cliff (I think it was the front). The bus is just balancing with people at places along its length, so with everyone right at one end it will be stable. Then send the smallest person down towards the gold. If he can reach it, he can bring it back a bit at a time: the bus will become increasingly stable as the gold is brought to the front, so only the first bit is critical. If the bus begins to tip as the person tries to go towards the gold, fashion a loop or lasso out of rope or clothes, and lasso some/all the gold and drag it towards the front.
Mick Potter, Petersfield
Smash out the middle windows as suggested, then smash in the front ones. Then get all but one of the gang to climb outside and clamber round to the front of the bus, using wing mirrors to hang on. This will increase the leverage, stabilizing the bus. The one inside can then safely go and get the bullion.
James Gilbert, Washington DC, USA
I moved everybody further back and let one get out and using the tow rope tie the front bumper to heavy rock.
Peter Murray, Epping Essex
Smashing the front windows in will not help, as the total weight in the bus is the same. All the gang should stand as near the front of the bus as possible. If the fuel tank is at the rear, start the engine and burn off sufficient fuel to enable the lightest man to collect rocks. They might want to keep some fuel to drive away (if they can drag the lightened vehicle off the cliff).
Jon Boston, Cambridge
They could take off their shirts and trousers and tie them together end to end to form a long loop. Then throw the loop over the gold and pull the gold towards the front of the bus to stabilise the weight. If the gold is too heavy to pull all at once, throw the clothes over the top of the gold and pull it back some at a time !
Rob Bull, Newbury, Berkshire
A simpler solution would be to move every person plus object within reach as far forward as possible. Then lean out of the front door and start loading soil onto the coach, without getting off. With enough soil to counterbalance a man's weight, a single person could start ferrying gold from back to front.
Colin Goddard, Baldock
1. Everyone gets as far as possible to front of bus and brings anything with weight.
2. The lightest person gets out (slowly) and starts passing rocks to be placed at front of bus (as many as possible).
3. Deflates front tyres.
4. Lightest person crawls to rear of bus and starts passing back gold to front of bus.
5. Bus now stable. Gold intact. Everyone survives. Croker says "bloody good show".
Jon , Felixstowe
Even as a kid when I watched it for the first time I had an instant solution that was better: Get the robbers as far forward as possible, taking out the glass and literally making a human "blob" as far forward as possible, even levering on the front bumper. This would I reckon double the amount of leverage allowing 1 man to approach the gold and remove one gold bar at at time and place it at the front of the vehicle - the coach would soon be heavily loaded at the front and firmly planted on its front wheels, which would still be full of air! Not difficult!
Mike, Preston, Lancs
Smashing in the front windows would not increase the weight there as the glass is already in the right place, and it was not possible for anyone to go to the rear of the coach in order to smash out those windows, or to drain the fuel tank. Maybe the best bet would have been for the gang to smash "in" the windscreen then hang off the front of the coach, thereby increasing the leverage of their weight and allowing the lightest man to go and collect rocks to stabilise it, before retrieving the gold. How then to carry it all away?
We only need to stabilize the bus, right? And then we can pull out the gold with glee. Using this equation M1xD1 = M2xD2 where M1 is the mass of the gold, D1 is the distance of the mass of gold from the new centre of gravity of the bus and M2 is the mass of the guys, D1 is the distance of the guys from the new centre of gravity of the bus. The variable here is the guys from the centre of gravity of the bus, D2. I'd suggest that they pack themselves tightly to their corner of the bus (even if it means leaning out the window), thereby increasing D2 and make a bag/sack with their shirts and make a rope to tie this bag/sack with their belts. Then they should hold onto the belt-rope and make the lightest of them all crawl on his belly very gently to the side of the bus with the gold (he must not stand since it will increase his potential energy) and slide the gold bars into the bag/sack. When he has a substantial amount, his colleagues may pull on the belt-rope. Soon the centre of gravity will move further to their end and stabilize the bus. I haven't watched the movie, just made this up using the flash animation in the page.
Samuel, Accra, Ghana