Problem 2. In a city on the main straight street, there are a school, a post office, and a cinema. The distance from the school to the post office is $1 \mathrm{~km} 215 \mathrm{~m}$, and the distance between the school and the cinema is one third less. What is the distance from the post office to the cinema?
Solution. The distance from the school to the post office is $1215 \mathrm{~m}$, and from the school to the cinema is $1215: 3=405 \mathrm{~m}$. This means that the cinema is closer to the school, and the distance from the cinema to the post office is $1215-405=810 \mathrm{~m}$.