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 ?
option
(a) 4
(b) 10
(c) 15
(d) 16

• here l.c.m of 2,4,6,8,10 and 12 is 120.
  so after every 120secor 2 minute they toll together.
  there are 30 minutes so no times they toll together=30/2=15
  hence ans is (c).
• 14 years agoHelpfull: Yes(14) No(19)
• take the lcm of the time given . you will get 120 sec as lcm then divide 30 min by 120 sec you will get the answer
  
• 9 years agoHelpfull: Yes(0) No(0)