inspired by mr dave here is one more coin trick. although this is quiet a common question for mba students lets see how tech freaks here go about it (in case if u know the answer already plz let others try first) here is the problem. there are ten coin minting machines.each coin manufactured must have an expected weight of 10 grams. but one of the machine develops a flaw and starts developing 9 gram coins instead. in what way can one figure out which machine is faulty by weighing just once.