A watch which gains 5 seconds every 3 minutes was set right at 9 a.m. What is the true time when the watch shows 6:15 p.m. that evening?
A
6:30 pm
B
6:08 pm
C
6 pm
D
6:18 pm
Correct Option - C
Explaination
Time from 9 a.m. to 6:15 p.m.
= 9 hours 15 minutes
= 555 minutes
3 minutes 5 seconds of this clock
= 3 minutes of correct clock
185 seconds of this clock
= 180 seconds of correct clock
1 minute of this clock
= (180/185) minutes of correct clock
555 minutes of this clock
= (180/185)*555
= 540 minutes
= 9 hours of correct clock
Correct time is 6 p.m.