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

• (30/2)+1=16 because at 0 sec they start tolling
• 13 years agoHelpfull: Yes(38) No(4)
• ans is d)16
  take lcm of 2,4,6,8,10,12 seconds
  the outcome is 120seconds.
  thats at 2mins once it rings.
  in 30mins it will rings 15times together
  in 0th second all bells rings together.
  so ans is 15+1=16.
• 13 years agoHelpfull: Yes(22) No(3)
• ans is c)15
  take lcm of 2,4,6,8,10,12 seconds
  the outcome is 120seconds.
  thats at 2mins once it rings.
  in 30mins it will rings 15times together
• 13 years agoHelpfull: Yes(14) No(15)
• 16
• 13 years agoHelpfull: Yes(8) No(1)
• 15
• 13 years agoHelpfull: Yes(3) No(14)
• it is given that bel rings at 2, 4, 6 which are multiples of 2 , so find multiples of 2 upto 30 i.e 15 so ans is 15
• 13 years agoHelpfull: Yes(3) No(10)
• the lcm of 2,4,6,8,10,12 is 120 i.e. they ring together after every 2min. so 15 times in 30 min.
• 13 years agoHelpfull: Yes(2) No(8)
• 16
  because lcm of 2,4,6,8,10,,12=120
  and then 2 minute some ring
  30/2=15
  15+1=16
  ans 16
• 4 years agoHelpfull: Yes(0) No(0)