Pipes cisterns and work time will account for about 1 or 2 questions in the GMAT math section. Questions from this topic appear in both variants - problem solving and data sufficient.

### Concepts Covered

A typical question that appear from this topic in the GMAT quant section is a word problems. The core idea covered in this chapter is similar to the one covered in Speed Time Distance. So, if you have a good grasp of Speed Time Distance, you will be able to understand and solve questions in this topic with a lot of ease. Wizako's GMAT Math Lesson Book in this chapter covers the following concepts:

- The chapter starts by explaining the relation between the time taken to complete a task (fill a tank) and rate at which the task is completed with illustrative examples. The reciprocal relation between time and fraction of work completed is explained in depth.
- There are 17 solved examples in questions related to pipes and cisterns. Some of the tough math questions in this topic are featured here.
- How to frame equations for work time questions when time taken to complete a task is provided?
- There are 14 solved examples for questions related to work and time. Shorcuts to few hard math questions in work time are provided.
- 24 exercise problems, 12 each in pipes & cisterns and work & time have been provided with the answer key and explanatory answers.
- A multiple choice test with 35 GMAT level questions with explanatory answers and answer key is provided in the Math work book.

Here is a typical solved example from this chapter.

### Sample Question

Pipe A fills a tank in 30 minutes. Pipe B can fill the same tank 5 times as fast as pipe A. If both the pipes were kept open when the tank is empty, in how many minutes will the tank be filled?

#### Explanatory Answer

Pipe B fills the tank 5 times as fast as pipe A.

Therefore, pipe B will fill the tank in one-fifth of the time that pipe A takes.

Pipe B will fill the tank in \\frac{30}{5}) = 6 minutes.

In 1 minute, pipe A will fill \\frac{1}{30}^{th}) of the tank and pipe B will fill \\frac{1}{6}^{th}) of the tank.

Therefore, together, the two pipes will fill \\frac{1}{30}) + \\frac{1}{6}) = \\frac{1 + 5}{30}) = \\frac{6}{30}) = \\frac{1}{5}^{th}) of the tank in a minute

Hence, the two pipes working together will take __5 minutes__ to fill the tank.

### Chapterwise details of Wizako's Math Lesson Books

Math Lesson Book 1

1 | Linear Equations | Details |

2 | Quadratic Equations | Details |

3 | Set Theory | Details |

4 | Sequences & Series | Details |

5 | Number Properties & Theory | Details |

6 | Inequalities | Details |

7 | Functions |