Question

two pipes a and b can fill a tank in 15 minutes and 25 minutes respectively. both pipes are opened together and pipe b is closed 5 minutes before the tank is filled completely. find the total time required to fill the tank​

Answer 1

Step-by-step explanation:

Given:

• Two pipes a and b can fill a tank in 15 minutes and 25 minutes respectively.
• Both pipes are opened together and pipe b is closed 5 minutes before the tank is filled completely.

To find:

• The total time required to fill the tank.

Solution:

A = 15 min

B = 25 min

The ratio = 15:25 = 3:5

In 1 minute A can fill 3 units and B can fill 5 units of work

Both A+B =(5+3)/75 = 8/75

A and B can fill the tank in 75/8 minutes

Let the required time be t be the pipes are open

B turned off before 5 minutes the tank gets filled

• 3t+5(t-5) = 75
• 3t+5t-25 = 75
• 8t -25 = 75
• 8t = 75+25
• 8t = 100
• t = 100/8
• t = 25/2
• t = 12 1/2 minutes

Therefore,

The total time required to fill the tank = 12 and half minute = 12.5 min

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