Problems : A watch which gains uniformly, is 5 min, slow at 8 o'clock in the morning on Sunday and it is 5 min.48 sec.fast at 8 p.m on following Sunday.
Solution : Time from 8 am on Sunday to 8 p.m on following Sunday = 7 days
12 hours = 180 hours
the watch gains (5+(5 4/5))min .or 54/5 min. in 180 hours
Now 54/5 min are gained in 180 hours.
Therefore 5 minutes are gained in(180*5/54*5)hours=83 hours-20 min.
=3 days 11-hrs 20-min.
therefore watch is correct at 3 days 11 hours 20 minutes after 8 a.m
of Sunday therefore it will be correct at 20 min.past 7 p.m on Wednesday