Question

pipe A can fill a Cistern in 5 hours and pipe B in 10 hours. both the pipes are opened together and after 2 hours pipe A is closed, how much time will the pipe B take to fill up the remaining part of the tank??

answer is 6 hours but how?
please answer properly step by step​

Answer 1

Answer:

A                        B

                                                                          5                        10

Total capacity of cistern = LCM (5,10) =                       10 units

Part filled by A and B in 1 hr =                            2                         1

Units filled by A and B together in 1 hr = A + B = 2 + 1 =  3 units

Part filled by A and B together (A + B) * 2 = 6         (because A is closed after 2 hrs)

Remaining part = 10 - 6 = 4

As A is closed, B will fill the remaining part in = 4 / 1 = 4 hrs

Step-by-step explanation:

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