an empty tankbe filled with aninlet pipe 'A' in 42 minutes. after 12 minutes an outlet pipe 'B' is opened which can empty the tank in 30 minutes. After 6 minutes another inlet pipe 'C' opened into the same tank, which can fill the tank in 35 minutes and the tank is filled find the time taken to fill the tank?

• in this question, we assume that by the time pipe A, B & C are open they continue to fill the tank until the tank is full.
  
  before pipe C is opened, pipe A & B together filled the 48/210 part of the tank
  as, 12/42 + 6(1/42 - 1/30)
  
  NOW, 1-(48/210)= 162/210 part is left which is to be fill be three pipes
  
  pipe A, B, C takes the reciprocal of (1/42 - 1/30 +1/35)min to fill the tank completely therefore 162/210 part can be fill in 81/2 minutes.
  
  therefore total time = 12 + 6 + 81/2 = 58.5 answer
  
  
• 11 years agoHelpfull: Yes(70) No(10)
• Rate at which A fill is 1/42 per min
  
  A filled for 12 min so tank filled by A will be 12/42
  
  Similarly B empty the tank for 6 min
  
  now the volume will be (18/42) -(6/30) = 8/35 because at the 6 min A has also filled.
  
  Now the amount left to be filled is (1-8/35) = 27/35
  
  Now C comes it fills 1/35 per minute.
  
  So from now the amount will be filled is (1/42+1/35-1/30) = 2/105 per minute
  
  So to fill the required amount it will take 105/2 * 27/35 = 40.5 min
  
  So total time is 12+6+40.5 = 58.5 min
  
  
• 11 years agoHelpfull: Yes(46) No(1)
• rate at which A fill is 1/42 per min
  A filled for 12 min so tank filled by A will be 12/42
  similarly B empty the tank for 6 min.. now the volume will be (12/42) -(6/30)
  let for x time c fill the tank.. volume will be (12/42) -(6/30)+(x/35) =1 as the tank is filled completely
  find x
  x=32
  total time is A+B+C=12+6+32=50
• 11 years agoHelpfull: Yes(11) No(25)
• solution of mayank is correct but on solving the equation for t, we get t=40.5
• 11 years agoHelpfull: Yes(6) No(9)
• 40.5 is the right answer.
• 11 years agoHelpfull: Yes(5) No(6)
• Ans. 58.5 Min
  
  For 12 + 6 min A i.e.. 18/42
  For 6 Min B i.e.. -6/30 or -1/5
  For rest all A-B+C together. So we can solve as below:
  
  18/42 - 6/30 = 9/21 – 1/5 = 45-21/105 = 24/105 Filled
  So,
  1 – 24/105 = 81/105 empty.
  
  ((1/42)-(1/30)+(1/35)) = (1050-1470+1260)/44100 = 840/44100 = 14/735
  
  Now
  81/105 * 735/14 = 40.5 Min
  Total = 18+40.5 = 58.5 Min ans.
  
• 11 years agoHelpfull: Yes(5) No(2)
• pls explain clearly with correct answer...better provide options also...
• 11 years agoHelpfull: Yes(2) No(2)
• pipe A worked for 12 minutes: thus tank filled (12/42)
  tank filled 12 parts out of 42 and 30 parts empty
  then pipe B worked for 6 minutes:thus (-6/30), meanwhile A filled it with (6/42)
  thus after 18 minutes:(18/42)-(6/30)i.e. 8/35 tank is full remaining 27/35 empty
  now pipe C is open and tank to be filled is 27/35
  thus:[(1/42)+(1/35)-(1/30)]t=(27/35)
  solving this we get t = 47.25 min
• 11 years agoHelpfull: Yes(1) No(8)
• plz help me frnz...kindly mail me the latest tcs ques on my id vermadisha88@yahoo.com.my apti is on 18th.plz help me....
• 11 years agoHelpfull: Yes(1) No(2)
• hi
  iif any one get question paper from vipul plese send me on my e-mail id
  "kalyan.karbhar100@gmail.com"
  
• 11 years agoHelpfull: Yes(0) No(11)
• ans. 35/9mins
• 11 years agoHelpfull: Yes(0) No(11)
• 49.5mins required to empty the tank
• 11 years agoHelpfull: Yes(0) No(6)