In a 100m race, A beats B by 15m, B beats C by 10m. If A beats C by 5sec, find the speed of C.

• A beats B by 15m
  means when A moves 100m B moves 85m.
  B beats C by 10m
  means when B moves 100m C moves 90m.
  =>when B moves 1m C moves .9m.
  =>when B moves 85m C moves .9*85m=76.5m.
  If A beats C by 5 sec
  =>c takes 5sec to moves 23.5m.
  =>c takes 1sec to moves 4.7m.
  =>speed=4.7m/sec.
• 11 years agoHelpfull: Yes(59) No(2)
• It's too simple,
  Here
  A=B+15,-------(i)
  B=C+10,-------(ii)
  (i)+(ii)
  A+B=B+C+25 => A-C=25, means when A moves 100 B moves 75.
  given in question A beats C by 5 seconds,
  So, C covered 25m in 5s,
  i.e, speed of C= 25m/5s=5m/s
• 11 years agoHelpfull: Yes(12) No(1)
• It's too simple,
  Here
  A=B+15,-------(i)
  B=C+10,-------(ii)
  (i)+(ii)
  A+B=B+C+25 => A-C=25, means when A moves 100 C moves 75.
  given in question A beats C by 5 seconds,
  So, C covered 25m in 5s,
  i.e, speed of C= 25m/5s=5m/s
• 11 years agoHelpfull: Yes(5) No(1)
• @Ritabrata : Can yu tell me how yu put
  =>c takes 5sec to moves 23.5m
  this line ????
• 11 years agoHelpfull: Yes(3) No(2)
• yes its 4.7m/sec
  
• 11 years agoHelpfull: Yes(2) No(0)
• A beats B by 15m, hence A->100m and B->85m
  B beats C by 10m, hnce B->85m and c->75m
  25m covered by A in 5 sec, speed of A=5m/sec
  time taken by A =20 sec
  time taken by C=25 sec
  speed of c=75/25
  =3m/sec
  is it wrong?????
• 11 years agoHelpfull: Yes(1) No(4)
• Distnc btw a and c is 25m I.e a covrs 25m in 5 sec...
  so speed of a is 5m/s...
  now time taken by a to cvr 100m is 20 sec.... so in 20 sec c cvrs 75m
  hence speed of c is 75/20=3.75m/s...
  this one is crct soltn with clr explntn....
• 10 years agoHelpfull: Yes(1) No(0)
• a goes 100m in 20 sec
  c goes in 20 sec 75m
  then c's speed is 75/20=3.75m/sec
• 11 years agoHelpfull: Yes(0) No(1)
• when A completed the race(ie 100m)-
  B was at 85m.
  therefore distance covered by B relative to A=85/100 m
  similarly when B completed,C was at 90 m,hence speed of C relative to B=100/90=0.9m
  
  hence we can say that-when A finished B was at 85m and C was at 0.9*85 m=76.5 m
  Difference of distances of A and C=100-76.5=23.5m
  
  now given that C will require 5 sec to cover this gap
  there speed of C=23.5/5=4.7 m/sec
• 9 years agoHelpfull: Yes(0) No(0)