Aptitude - Pipes and Cistern

Exercise : Pipes and Cistern - Data Sufficiency 2
Directions to Solve

Each of the questions given below consists of a question followed by three statements. You have to study the question and the statements and decide which of the statement(s) is/are necessary to answer the question.


If both the pipes are opened, how many hours will be taken to fill the tank?


The capacity of the tank is 400 litres.


The pipe A fills the tank in 4 hours.


The pipe B fills the tank in 6 hours.

Only I and II
Only II and III
All I, II and III
Any two of the three
Even with all the three statements, answer cannot be given.
Answer: Option

  II. Part of the tank filled by A in 1 hour = 1

III. Part of the tank filled by B in 1 hour = 1

(A + B)'s 1 hour's work = 1 + 1 = 5
4 6 12

A and B will fill the tank in 12 hrs = 2 hrs 24 min.

So, II and III are needed.

Correct answer is (B).