Praveen's Blog

An Eternal Quest for Incremental Improvement

Puzzle of the week - Week #3

There are ten coin machines. Each machine produces coins that weigh 10 g, expect one faulty machine which produces coins that weigh 9 g. You are given with an electronic weighing scale. You can take any number of coins from any machine and use the weighing scale. What would be the minimum number of usage of the weighing scale to find out the faulty machine?