Question

water tank is 2/7th full. Pipe A can fill the tank in 10 minutes and pipe B can empty it in 7
minutes if both the pipes are open, how long will it take to empty or fill the tank completely?

Answer 1

Answer:

Pipe A can fill a tank in 10 minutes and pipe B can empty it in 6 minutes. If both the pipes are open,how long will it take to empty or fill the tank completely.

Step-by-step explanation:

Explanation: Clearly,pipe B is faster than pipe A and so,the tank will be emptied.

Answer 2

Answer:

So, the tank will be emptied in 6.33 minutes.

Step-by-step explanation:

Pipe A in 1 minute fills $\frac{1}{10}$ part and

Pipe B in 1 minute empties $\frac{1}{7}$ part.

Work done by pipe( A + B) in 1 min =$\frac{1}{7} -\frac{1}{10} =\frac{10-7}{70} = \frac{3}{70}$

Hence $\frac{3}{70} :\frac{2}{7}$ :: 1 : x

$\frac{3(7)}{70(2)} = \frac{1}{x}$

$\frac{3}{20} = \frac{1}{x}$

x = $\frac{20}{3}$ = 6.33

Therefore 6.33 minutes

so, the tank will be emptied in 6.33 minutes.