Question

Pipe a can fill the cistern in 15 hours and pipe b alone can fill it in 30 hours both the pipe are opened together but pipe a closed 3 hours before the complete filling of cistern .The whole cistern is filled in.​

Answer 1

Answer:

I HOPE IT IS HELPFUL.

THANK YOU

Answer 2

Given: Pipe A can fill the cistern in 15 hours and pipe B alone can fill it in 30 hours.

If Both pipes are opened cistern fill at,

$\frac{1}{15}+\frac{1}{30}=\frac{2+1}{30}$

$\frac{1}{15}+\frac{1}{30}=\frac{3}{30}$

$\frac{1}{15}+\frac{1}{30}=\frac{1}{10}$

Both pipes can fill the Cistern in 10 hours.

According to the given statement, Pipe A is closed 3 hours before

In 1 hour both pipes filled =  $\frac{1}{10}$ part of the cistern.

In 7 hours both pipes filled =  $\frac{7}{10}$ part of the cistern.

$\frac{3}{10}$ part of the cistern will be filled by pipe B.

In 1 hour pipe A filled =  $\frac{1}{30}$ part of the cistern.

We can also say that,

$\frac{1}{30}$ part of the cistern filled by Pipe A in 1 hour.

$\frac{3}{10}$ part of the cistern will be filled =  $\frac{3}{10}\times \frac{30}{1}\times 1$

$\frac{3}{10}$ part of the cistern will be filled =  9 Hours

The whole cistern is filled = $7+9$

The whole cistern is filled in 16 Hours.