Subject: General Aptitude · Chapter: H.C.F. and L.C.M. of Numbers · Exam: 2007 · Marks: · Difficulty:
An electronic device makes a beep after every 60 sec. Another device makes a beep after every 62 sec. They beeped together at 10 a.m. The next time, when they would beep together at the earliest is
(a)10.30 a.m.
(b)10.31 a.m.
(c)10.59 a.m.
(d)11 a.m.
Answer
Answer (as printed): B
Explanation
Interval of change = (L.C.M. of 60 and 62) sec = 1860 sec $=31 \mathrm{min}$. So, the devices would beep together 31 min after 10 a.m., i.e., at 10.31 a.m.