In a circular race track of length 100 m, three persons A, B and C start together. A and B start in the same direction at speeds of 10 m/s and 8 m/s respectively. While C runs in the opposite at 15 m/s. When will all the three meet for the first time on the 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(17) No(4)
• Ans:100 seconds
  A = 10m/s
  B = 8m/s
  C = 15m/s
  A and B same direction But C opposite direction
  race = 100m
  100/(10-8)=50seconds
  for every 50secs A and B will meet
  50sec*10m/s=500m
  50sec*8m/s=400m
  when A & B meets C will be in opposite direction of A & B
  at 100sec
  A->100*10=1000m
  b->100*8=800m
  at this all of them will meet
• 12 years agoHelpfull: Yes(7) No(26)