Subject: General Aptitude · Chapter: H.C.F. and L.C.M. of Numbers · Exam: 2006 · Marks: · Difficulty:
Six bells commence tolling together and toll at intervals of 2, 4, 6, 8, 10 and 12 seconds respectively. In 30 minutes, how many times do they toll together?
(a)4
(b)10
(c)15
(d)16
Answer
Answer (as printed): D
Explanation
L.C.M. of 2, 4, 6, 8, 10, 12 is 120.So, the bells will toll together after every 120 seconds, i.e., 2 minutes. In 30 minutes, they will toll together $\left[\left(\frac{30}{2}\right)+1\right]=16$ times.
Explanation as extracted from the printed page; notation may be imperfect.