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. When was it correct?
Answer
Answer (as printed):
Explanation
Time from 8 a.m. on Sunday to 8 p.m. on following Sunday = 7 days 12 hours = 180 hours. 4 54 ∴ The watch gains 5 + 5 min . or min . in 180 hrs. 5 5 54 Now min. are gained in 180 hrs. 5 5 ∴ 5 min. are gained in 180 × × 5 hrs. = 83 hrs 20 min. = 3 days 11 hrs 20 min. 54 ∴ Watch is correct 3 days 11 hrs 20 min. after 8 a.m. of Sunday. ∴ It will be correct at 20 min. past 7 p.m. on Wednesday.
Explanation as extracted from the printed page; notation may be imperfect.