The dashed frame shows a clock in a mirror at the end of a corridor. What is the actual time?

The image shows 12:10. Since 11:60 - 12:10 would be negative, use 23:60 - 12:10 = 11:50. Check with the hands: the minute hand on 2 in the image is really on 10 (50 minutes), and the hour hand just after 12 is really just before 12. (12:50 keeps the hour; 11:10 keeps the image's minutes.)