Elena Lucrezia Cornaro Piscopia, a 17th-century Venetian philosopher and mathematician, was the first woman to obtain a PhD. At this time, Italian society was passionate about debates on philosophy and mathematics, considered inseparable branches of knowledge. Mathematical logic problems are a clear example.

The following problem of mathematical logic is proposed.

We have 10 sacks with 100 balls each. All the balls weigh 10 g, except those in one of the bags, in which they all weigh 9 g.

Reason how you can find out which is the different bag using the scales only once.