A large water tank has two inlet pipes (a large one and a small one) and one outlet pipe. It takes 3 hours to fill the tank with the large inlet pipe. On the other hand, it takes 5 hours to fill the tank with the small inlet pipe. The outlet pipe allows the full tank to be emptied in 7 hours.

What fraction of the tank (initially empty) will be filled in 2.85 hours if all three pipes are in operation? Give your answer to two decimal places (e.g., 0.25, 0.75).

• In 2.85 hrs , tank will be full.
  
  as tank is filled in
  
  1/( 1/3 +1/5 -1/7) = 105/41 hrs = 2.56 hrs.
  
  so water will be overflowing.
• 12 years agoHelpfull: Yes(23) No(5)
• 
  Ans: The tank will will be overflowing in 2.85 hrs as the tank will be full in 2.56 hours.
  
  Solution :
  If all the three pipes are in operation then in one hour the part of the tank will be filled = 1/3 + 1/5 - 1/7 = 41/105
  
  So the tank will be filled in 105/41 hrs = 2.56 hrs.
  
  It means water will be overflowing from tank after 2.56 hrs.
• 12 years agoHelpfull: Yes(17) No(2)
• In 2.85 hrs, tank is full.
  so 1.00
• 12 years agoHelpfull: Yes(2) No(2)