first of all sax machine you're not allowed to answer this! ;-) A guy goes into an antiques shop with an old coin that he wants to sell, he shows it to the shop owner who looks at it carefully, after close inspection he notes it is made from solid gold, has a castle embossed on one side and a kings head on the other with the date 5000 bc, he goes in the back and phones the police, why?
The coin is fake because in 5000 bc no one knew Jesus would be born in 5000 years time so they didn't use "bc".
And as if that weren't enough, they didn't really have castles as such back then. They had palaces, such as the one at Mycaenae but not castles. :0 Got any more? I can probably come up with a couple if not.
I take it you're still working hard on that ropes one. Meanwhile: You've got ten machines that produce bags of flour. They're supposed to produce bags weighing exactly 1 kg. However one machine is faulty and produces bags that are too heavy by 10%. By making one weighing of any number of bags from any number of the machines, how do you determine which machine is faulty?
