Problem 3. When Maria woke up and looked at the clock, she found that one quarter of the day and night had passed. Her first class will start in 75 minutes, and she will stay at school for 4 hours and 50 minutes. What time will Maria leave school and head home?
Solution. Since $24: 4=6$, at the moment Maria looked at the clock it was 6 o'clock. The first school hour will start after 75 minutes, which means at 7:15. She will stay at school for another 4 hours and 50 minutes, so she will leave for home at

$$
7:15 \text { min. }+4 \text { hr. } 50 \text { min. }=12:05 \text { min. }
$$