A watch goes fast by 15 minutes compared to the right time everyday. If it is corrected and set to the standard time at 120' clock at noon, which of the following will be the time shown by it at 4 : 00 a.m. in the morning?
(a)3 : 45 a.m.
(b)4 : 10 a.m.
(c)4 : 15 a.m.
(d)4 : 30 a.m.
Answer
Answer (as printed): B
Explanation
Duration from 12 noon to 4:00 a.m. = 16 hours. Time gained in 24 hours = 15 min. Time gained in 16 hours $=\left(\frac{5}{24} \times 16\right) \min =10 \mathrm{min}$. Hence, time shown by the watch at 4 a.m. = 4:10 a.m.