# Aptitude - Pipes and Cistern

- Pipes and Cistern - Formulas
- Pipes and Cistern - General Questions
- Pipes and Cistern - Data Sufficiency 1
- Pipes and Cistern - Data Sufficiency 2

*Directions to Solve*

Each of the questions given below consists of a statement and / or a question and two statements numbered I and II given below it. You have to decide whether the data provided in the statement(s) is / are sufficient to answer the given question. Read the both statements and

- Give answer (A) if the data in Statement I alone are sufficient to answer the question, while the data in Statement II alone are not sufficient to answer the question.
- Give answer (B) if the data in Statement II alone are sufficient to answer the question, while the data in Statement I alone are not sufficient to answer the question.
- Give answer (C) if the data either in Statement I or in Statement II alone are sufficient to answer the question.
- Give answer (D) if the data even in both Statements I and II together are not sufficient to answer the question.
- Give answer(E) if the data in both Statements I and II together are necessary to answer the question.

How much time will the leak take to empty the full cistern? | |

I. | The cistern is normally filled in 9 hours. |

II. | It takes one hour more than the usual time to fill the cistern because of la leak in the bottom. |

** I.** Time taken to fill the cistern without leak = 9 hours.

Part of cistern filled without leak in 1 hour = | 1 |

9 |

**II.** Time taken to fill the cistern in presence of leak = 10 hours.

Net filling in 1 hour = | 1 |

10 |

Work done by leak in 1 hour = | 1 | - | 1 | = | 1 | ||

9 | 10 | 90 |

Leak will empty the full cistern in 90 hours.

Clearly, both I and II are necessary to answer the question.

Correct answer is (E).

How long will it take to empty the tank if both the inlet pipe A and the outlet pipe B are opened simultaneously? | |

I. | A can fill the tank in 16 minutes. |

II. | B can empty the full tank in 8 minutes. |

I. A's 1 minute's filling work = |
1 |

16 |

II. B's 1 minute's filling work = |
1 |

8 |

(A + B)'s 1 minute's emptying work = | 1 | - | 1 | = | 1 | ||

8 | 16 | 16 |

Tank will be emptied in 16 minutes.

Thus, both I and II are necessary to answer the question.

Correct answer is (E).