A clock is 3 minutes slow at 10:30 AM and 9 minutes slow at 4:30 PM. At what time (in AM) will it show the correct time?
Show answer & explanation
Correct answer: B
Explanation
3 × 60 = 180 minutes = 3 hours
10:30 AM + 3 hours = 1:30 PM
But 1:30 PM is not in the given options.
So, when asked about the morning time according to the options, after completing the cycle:
Clock error in 12 hours:
12 hours × 1 minute per hour = 12 minutes
The clock is 3 minutes slow, so next:
(12 − 3) hours = 9 hours later, the clock will show the correct time.
10:30 AM + 9 hours = 7:30 PM
In the morning cycle:
7:30 PM − 12 hours = 7:30 AM