Faulty coin puzzle
We have ten sacks and each of sack having 1000 coins. Each coin weighs 10 grams. One of sack is having faulty coins whose weight is 11 grams. We have to find out faulty sack. We can use weigh machine only one time. How to find faulty sack ?
Keep on adding the sack on the weighing machine. The moment weight increases by 11 Kg we get to know that the recent one has faulty coins
ReplyDeleteParag, You can not keep putting weights and have the readings.
DeleteYou can use machine one time means one time reading only.
Take out coins in the following sequence :
ReplyDeleteSack 1 : 1 Coin
Sack 2 : 2 Coins
Sack 3 : 3 Coins
...
...
Sack 10 : 10 Coins
Now weigh the collected coins ..
Ideally the weight should be 55 * 10 grms = 550grms
The difference in the Actual Weight and the expected Weight will give you the Sack Number.
(Actual Weight - 550) = Sack Number.