You got 20 buckets in order from 1 to 20. Each bucket is numbered. (As follows: bucket #1, bucket #2, etc) All 20 buckets have the same amount of coins. 19 buckets have coins that weight 1 gram each. 1 bucket have coins that weight 2 grams each. The 1 gram and the 2 gram coins, look exactly the same. You got an electronic scale with 1 gram resolution and just one chance to weight. I which bucket (numbered from 1 to 20) are the 2 gram coins?