A set an alarm in 2 different clocks.first clock ring after every 2 hours.second clock rings after every 1 hour and 30 min.if both rang at 1pm..what will be the next time both ring together?

• lcm of 2,1.5 is 6
  i.e. for every 6 hours they will rang at a time
  therefore at 7pm they will rang
  
• 10 years agoHelpfull: Yes(1) No(0)
• Current time according to question is 1 pm.
  then Second clock rings at 2:30 pm and then 1st clock at 3 pm and then again second clock rings at 4 pm and 1st clock rings at 5pm and then second clock rings at 5:30 pm and both clocks ring at 7 pm ..
  So the time when both clock rings at same time is 7 pm.
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• LCM of 120 mints and 90 mints is 360 mints i.e. 6 hrs,so they again ring at 7 p.m.
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• 1st alarm 2 4 6
  2nd alarm 1 1/2, 3 ,4 1/2, 6 so after six hours both ring together.so at 7pm
  
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