There are many, many puzzles about clocks and time. In the nineteenth century, both Henry Dudeney and Sam Loydd designed a number of them, and in a future post I may collect them.
1) Basics*/*****
Today I encountered this problem on twitter, posed by a teacher for his students in primary school. Whisper your solution in the ear of the teacher to enter the classroom.
2) Advanced***/*****
You can check your solution here
New puzzles are published at least twice a month on Fridays.
justpuzzles 