A watch which gains 5 sec. in 3 min. was set right at 7 a.m. In the afternoon of the same day , when the watch indicated quarter past 4 o'clock , the true time is :

• 4 pm
  
  Gaining 5 sec. in 3 min means when it shows 185 sec, actually time elapsed is 180 sec.
  Total time between 7 am to 4.15 pm = (9x3600 + 15x60) sec = 33300 sec.
  So when watch shows 33300 sec, actual time elapsed=33300x180/185 =32400 sec=32400/3600=9 hrs.
  Hence true time= 7 am+9 hrs = 4 pm.
• 7 years agoHelpfull: Yes(0) No(0)