Folklore

The volume of a bottle of kvass is 1.5 liters. The first person drank half of the bottle, the second drank a third of what was left after the first, the third drank a quarter of what remained from the previous, and so on, the fourteenth drank a fifteenth of what was left. How much kvass is left in the bottle?
Note that if we decrease some quantity by $1 / n$ of its part, then $(n-1) / n$ of this quantity remains. Therefore, the remaining volume of kvass is $1.5 \cdot 1 / 2 \cdot 2 / 3 \cdot \ldots \cdot 14 / 15=1.5 \cdot 1 / 15=0.1$ liter.

## Answer

0.1 liter.