Two bank robbers, Ron and Jon, have managed to steal 42 crates of gold and silver bars from a bank, 392 of the bars they stole being gold.

Of the 42 crates, there are only two distinctive types regarding the amount and total worth of the bars that each crate contains. One type of crate contains 11 bars and is worth £140k, the other contains 20 bars and is worth £280k.

Jon, being the brains behind the operation, was elected to calculate how the takings would be divided between him and Ron and decided that he would take all of the crates that contained 20 bars and are worth £280k and leave the rest to Ron.

Ron isn't very happy that he's been left with the crates that are individually half as valuable as Jon's. Given that each gold bar is worth £15k and each silver bar is worth £10k, can you help Ron work out how much money in material value Jon has deviously given himself more than he has Ron?