Sushma has a dentist appointment at 7 : 20 in the evening. While entering the dentist’s office, she saw reflection of the wall clock. The hands of clock read 4 : 40. She knew that this being the reflection of the clock, the time she read is not the correct time. What is true regarding her.

In a mirror clock, the reflected time and actual time are symmetric around 12:00 (for hour hand) and 6:00 positions. The sum of reflected and actual positions equals 12. For 4:40, the reflection calculation: hour 4 reflects to 8 (since 4+8=12), minutes 40 reflect to 20 (since 40+20=60). So the actual time is 8:20. Since her appointment was at 7:20, she is exactly on time.