there are 12 pipes that are connected to a tank.some of them are fill pipes and the others are drain pipes.each of the fill pipes can fill the tank in 8 hours and each of the drain pipes can drain the tank completely in 6hours.if all the pipes are kept open, the empty tank gets filled in 24hours. how many of the 12pipes are fill pipes?

• let x pipes are fill pipes
  so
  (x/8)-((12-x)/6)=1/24
  on solving x=7 ans
• 12 years agoHelpfull: Yes(22) No(0)
• Let there be 'n' fill pipes attached to the tank.
  
  Therefore, there will be 12 - n drain pipes attached to the tank
  
  Each fill pipe fills the tank in 8 hours. Therefore, each of the fill pipes will fill th of the tank in an hour.
  
  Hence, n fill pipes will fill of the tank in an hour.
  
  Each drain pipe will drain the tank in 6 hours. Therefore, each of the drain pipes will drain th of the tank in an hour.
  
  Hence, (12 - n) drain pipes will drain th of the tank in an hour.
  
  When all these 12 pipes are kept open, it takes 24 hours for an empty tank to overflow. Therefore, in an hour th of the tank gets filled.
  
  Hence, .
  
  i.e. or 7n - 48 = 1 => 7n = 49 or n = 7.
  
• 12 years agoHelpfull: Yes(3) No(2)
• x- fill pipes , y - drain pipes
  x+y = 12 -----> 1
  8x-6y = 24 => 4x-3y = 12 -----> 2
  solving eqns 1 and 2 ,we get,
  x= 7
• 5 years agoHelpfull: Yes(1) No(0)
• my ans is 7
• 12 years agoHelpfull: Yes(0) No(1)