Question

31. Six pipes are fitted to a water tank. Some of these are
inlet pipes and the others outlet pipes. Each inlet
pipe can fi.. the tank in 9 h and each outlet pipe can
empty the tank in 6 h. On opening all the pipes, an
empty tank is filled in 9 h. The number of inlet pipes​

Answer 1

Answer:

Number of Inlet pipes = 4

Step-by-step explanation:

Inlet pipe can fill Tank in 9 hr

Tank filled by inlet pipe in 1 hr  = 1/9

outlet pipe can empty Tank in 6 hr

Tank emptied by outlet pipe in 1 hr  = 1/6

Total pipe = 6

Let say inlet Pipe = P

then outlet pipe = 6 - P

Tank filled in 1 hr  =  P/9  - (6-P)/6  

= (1/18) ( 2P  - 18 + 3P)

= (5P -18)/18

Tank filled in 9 hrs = 9( 5P -18)/18  =  (5P -18)/2

=> (5P -18)/2 = 1

=> 5P - 18 = 2

=> 5P = 20

=> P = 4

Number of Inlet pipes = 4

Answer 2

Step-by-step explanation:

that given answer is short cut medhod