Question

pipe A can fill cistern in 6 hrs and pipe B can fill it in 8 hrs. Both the pipes are opened and after two hours, pipe A is closed. How much time will B take to fill the remaining part of the tank?
​

Answer 1

Answer:

Step-by-step explanation:

Pipe A take time to fill cistern = 6 hrs

Work done by pipe A in 1 hr = 1/6

Pipe B take time to fill cistern = 8 hrs

Work done by pipe B in 1 hr = 1/8

Work done by both pipe in 2 hrs = 2×(1/6 + 1/8 )

                                                      = 2× 7/24

                                                      = 14/24

Remaining work = 1 - 14/24

                            = 10/24

Time taken to fill remaining cistern by B alone = Remaining work/  one hrs work

= 10/24 ÷ 1/8

= 10/3 hrs = 3 1/3 3 hrs 20 min

​