Six bells start ringing together and ring at intervals of 4, 8, 10, 12, 15 and 20 seconds respectively. how many times will they ring together in 60 minutes ?
A. 31
B. 15
C. 16
D. 30
Answer: Option A
Solution (By Examveda Team)
LCM of 4, 8, 10, 12, 15 and 20 = 120 120 seconds = 2 minutes Hence, all the six bells will ring together in every 2 minutes Hence, number of times they will ring together in 60 minutes = $$1 + \frac{{60}}{2}$$= 31
This Question Belongs to Arithmetic Ability >> Number System
Could you please explain why 1 is being added .
When they start ringing, it was zero minutes. Say if they start 1 PM, then they rings at 1PM then 1:02 and so on. Understand @Palak?
if 2 minutes they ring together then in 60 min 60/2 but why 1 is being added?
if 2 minutes they ring together then in 60 min 60/2 but why 1 is being added?