Four bells will ring at intervals of 18, 24, 32 and 40 seconds. If they begin by ringing together what time will elapse before they ring together again?

a. 1000 min
b. 2000 min
c. 1440 min
d. 1560 min

• take the lcm of 18,20,32 and 40=1440
• 12 years agoHelpfull: Yes(9) No(3)
• the LCM of 18,20,32 and 40 = 1440 sec.= 1440/60= 24 min.
  the bells ring together every 24 min.
  so 24*65=1560 min.
  option (d) is correct
• 12 years agoHelpfull: Yes(5) No(5)
• Find the LCM of 18,20,32 and 40=1440s or 144o seconds
  The answer would be Option C( not in minutes but in seconds)
• 12 years agoHelpfull: Yes(4) No(1)
• the Option (c) is also correct
  because 24*60=1440 min
• 12 years agoHelpfull: Yes(3) No(3)