After 12 days, i.e., after 12 × 24 hours, Clock A will gain 48 minutes and will slow down at 12:48 noon.
After 12 days, i.e., after 12 × 24 hours, Clock B will lose 16 minutes and will show 11:44 a.m.
The two clocks will show the same time after 135 days.
The time difference has to be 12 hours between them = 720 minutes.
A will gain 540 minutes in 135 days.
B will lose 180 minutes in 135 days.
Total 720 minutes.
Further, if we consider only the time then the problem becomes simpler.
Total difference of minutes between the times shown by the clocks after 36 hours
⇒
minutes difference in 1 day
⇒ 12 × 60 minutes difference in
×12×60 = 135 days