Six bells commence tolling together &toll at intervals 2,4,6,8,10,12 seconds respectively.In 30 minutes how many times they toll together?
a)4 b)10 c)15 d)16

• LCM of 2,4,6,8,10,12 is 120.
  Sp bells will toll together after every 120 seconds = 2 min.
  hence
  in 30 min they will toll together (30/2)+1 = 16 times
• 10 years agoHelpfull: Yes(9) No(1)
• LCM(2,4,6,8,10,12)=120 sec
  
  After120sec all troll at single time
  So total sec in 30 min = 60*30sec
  Total no of toll =60*30/120=15times
  
• 10 years agoHelpfull: Yes(1) No(6)
• tk the lcm of 2 4 6 8 10 12 which is 120 scnd or 2 min and dvd 30 by 2 which is 15(ans)
• 10 years agoHelpfull: Yes(1) No(5)
• As per the question all the bells started tolling at the same time.
  Since they toll at an interval of 2,4,6,8,10 and 112 seconds, the will toll together again after each 120 seconds(LCM of 2,4,6,8,10,12 is 120).
  Or we can say that they toll together after each 2 minutes.
  therefore in 30 minutes they will toll for (30/2) times, that is 15 times.
  But as they started at the same time, hence they will toll for (15+1)times, that is 16 times in 30 minutes...
• 5 years agoHelpfull: Yes(0) No(0)