A clock is displaying correct time at 9am on Mon- day. If the clock loses 12 minutes in 24 hours, then the actual time when the clock indicates 8:30pm on Wednesday of the same week is [DMRC—Customer Relationship Assistant (CRA) Exam, 2016]
(a)8 pm
(b)7 pm
(c)9 pm
(d)8: 59 : 45 pm
Answer
Answer (as printed): C
Explanation
Time interval from 9 am on Monday to 8 : 30 pm on Wednesday = ( 24 × 2.5 ) − 0 : 30 hours = 60 – 0 : 30 hours 833 = 59 hours 30 minutes 30 1 = 59 = 59 60 2 119 = hours 2 Also 24 hours – 12 minutes = 23 hours 48 minutes 48 4 119 = 23 + = 23 hours = hours 60 5 5 119 hours of this clock = 24 hours of the correct clock 5 119 24 × 5 119 ∴ hours of this clock = × = 60 hours 2 119 2 60 − 119 hours 2 120 − 119 1 = hours = hours = 30 minutes 2 2 Hence, the correct time is 30 minutes after 8 : 30 pm. i.e. 9 pm.
Explanation as extracted from the printed page; notation may be imperfect.