coin problem

Thread Starter


Joined Oct 20, 2014
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


Joined Apr 11, 2010
Take one coin from the first machine, two from the second machine, and so on. The difference between the actual weight and expected weight is the number of the machine producing 9 gram coins.