In a circular track of length 100m, three persons A, B and C start together. A and
B in the same direction at speeds of 10m/s and 8m/s respectively. While C runs in
the opposite direction at 15 m/s. When will all three meet for the first time after the start?

• A takes (100m) / (10m/s) = 10s to finish one complte round.
  B takes (100m) / (8m/s) = 12.5s to finish one complte round.
  C takes (100m) / (15m/s) = (20/3)s to finish one complte round.
  For them to meet, the time will be LCM of above three times ie LCM(10,12.5,20/3)
  = LCM(10/1,25/2,20/3) =100sec
  
• 9 years agoHelpfull: Yes(10) No(0)
• time of first meeting=circumference /relative speed
  for A and B=100/10-8 =50
  for A and C=100/15-10=20
  Lcm of (50,20)=100 sec
• 9 years agoHelpfull: Yes(5) No(2)
• Tab=(100/10-8)
  Tac=(100/10+15)
  ans=LCM(Tab, Tac)=100seconds.
• 9 years agoHelpfull: Yes(3) No(0)
• A takes (100m) / (10m/s) = 10s to finish one complte round.
  B takes (100m) / (8m/s) = 12.5s to finish one complte round.
  C takes (100m) / (15m/s) = (20/3)s to finish one complte round.
  For them to meet, the time will be LCM of above three times ie LCM(10,12.5,20/3)
  = LCM(10/1,25/2,20/3) =100sec
• 9 years agoHelpfull: Yes(1) No(0)
• for A and C = 100 /15+10=4
  @NIPUN
• 9 years agoHelpfull: Yes(0) No(0)