Question

three pipes have diameters 2cm,3cm,4cm.The amount of water flowing in by each pipe being proportional to the square of the diameters.The biggest pipe when open can alone fill the entire pool in just 120 minutes.When all the pipes are opened together the pool would be filled in how much time?​

Answer 1

Answer: B) 32 min

Explanation:

Given that the diameters of the three pipes are 2 cm, 3 cm and 4 cm

From the given data,

Amount of water from three pipes is 4 units, 9 units and 16 units.

Let the capacity of cistern be 'p' units.

∴ p/58 = 16

⇒ p = 928 units.

In 1 minute, quantity to be filled by 3 pipes = 29 units

∴ Total time required = 928/29 = 32 minutes.

Answer 2

Answer:

60

Step-by-step explanation:

Given that the diameters of the three pipes are 2 cm, 3 cm and 4 cm

From the given data,

Amount of water from three pipes is 4 units, 9 units and 16 units.

Let the capacity of cistern be 'p' units.

∴ p/120 = 16

⇒ p = 1920units.

In 1 minute, quantity to be filled by 3 pipes = 29 units

∴ Total time required = 1920/29 = 60 minutes.