Q142
Arithmetic
A clock fixed on the wall shows a time of 4 : 25. The time shown by its image on a plane mirror fixed to the opposite wall will be
- a.8 : 35
- b.7 : 25
- c.7 : 35
- d.8 : 25
Answer: (C) 7 : 35
A plane mirror reverses the dial left-to-right, so the mirror time is obtained by subtracting the actual time from 12 hours (written as $11:60$): $11:60 - 4:25 = 7:35$. Check: the two times add up to 12 hours ($4:25 + 7:35 = 12:00$). (A) and (D) wrongly subtract the hour from 12 without borrowing; (B) reverses only the hour hand and leaves the minutes unchanged.