Problem 2. Masha's classes at school end at 13:00, and her mother picks her up by car, and they drive home. One day, the classes ended at 12:00, and Masha started walking home. On the way, she met her mother, who, as usual, drove to pick up her daughter at 13:00 at the school. Then Masha and her mother drove home in the car, and they arrived 12 minutes earlier than usual. At what time did Masha meet her mother on the road? (The speeds of Masha and her mother are constant, and no time is spent on getting into the car.)
Answer: $12: 54$
Solution. Let Masha walk a distance of $l$. Then, on the way to school and on the way back, her mother drives $l$ less than usual. This means that the mother covers a distance of $2l$ in 12 minutes. Therefore, the distance $l$ she covers in 6 minutes. From this, it follows that the mother met Masha 6 minutes before she usually arrives at school. Thus, their meeting occurred at $12: 54$.

## Criteria

4 6. A complete and justified solution is provided.

In the absence of a correct solution, the highest applicable criterion from those listed below is used:

3 b. An arithmetic error is made in a correct solution, not affecting the course of the solution.

1 b. The correct answer is provided, but there is no justification.

0 6. The problem is not solved or is solved incorrectly.