A boy leaves home in the morning to go to school. At the moment he leaves the house he looks at the clock in the mirror. The clock has no number indication and for this reason the boy makes a mistake in interpreting the time (mirror-image). Just assuming the clock must be out of order, the boy cycles to school, where he arrives after twenty minutes. At that moment the clock at school shows a time that is two and a half hours later than the time that the boy saw on the clock at home.
What time the boy reaches school???

Right.

1: He saw it in the mirror, and it took 20 minutes to get to school. Therefore, he must have have left when he thought it was 10:00, but it was in fact 12:10. So he left.

2: He arrived at school after 20 minutes, and it was 12:30 by the clock at the back of the classroom, which is two and a half hours later that he thought it was when he left home.

Yes?