Question

Pipe A can fill a tank in 15 minutes and pipe B
can drain 40 litre per minute. If both the pipes
are opened together, the cistern is full in 45
minutes, find the capacity of the cistern.​

Answer 1

Answer:

Part filled in 4 minutes =4(1/15+1/20) = 7/15

Remaining part =(1-7/15) = 8/15

Part filled by B in 1 minute =1/20 : 8/15 :: 1:x

x = (8/15*1*20) = 1023min = 10min 40sec

The tank will be full in (4 min. + 10 min. + 40 sec.) = 14 min. 40 sec

Answer 2

Step-by-step explanation:

• Pipe A will fill a tank in a time of 15 minutes
• Pipe B will drain water in a time of 40 litres / minute
• So pipe A will fill and tap opened together in a time of 45 minutes.
• Work done by both pipes in one minute will be
•                                   1/m – 1/n
• Where m is time taken to fill the tank by pipe A and n is the time taken to empty the tank by pipe B.
•   So work done = 1/15 – 1/n
• Now work done = 1/45
•          1/45 = 1/15 – 1/n
•            1/n = 1/15 – 1/45
•            1/n = 2/45
•             Or n = 45/2 minutes.
• Therefore the draining time of water is 45/2 minutes.
• Now the tap drains at the rate of 40 litres/min and work done by tap is 45/2 minutes.
• Hence volume of the tank = 40 x 45/2
•                                             = 900 litres.

Reference link will be

https://brainly.in/question/48206120