You have 10 boxes with 10 coins each. All the coins from 9 of those boxes(all 90 of them) all weigh 1g. However the other box has coins which all weigh 1.1g. You have a scale that measures the weight of the load you put on. How can you determin which box has the 1.1g coins just by weighing one load of any combination of these 100 coins?