Pipes & Cisterns

Duration: 1 hr 12 min

This video lesson is available to enrolled students.

Return to /learn/DSSSB-TGT-COMPUTER-SCIENCE-COMPLETE-COURSE/arithmetical-numerical-ability/pipe-and-cistern/basic-concepts-formulas-and-terminology/asset-pipes-cisterns-15595 after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. Section A: General Awareness: Polity, Physics, Biology, Chemistry, Static General Knowledge, History, Geography, Indian Economy, GK- Current Affairs, Evolution of Indian Banking (Banking & Financial Awareness), Environment
  3. Section A: General Intelligence & Reasoning ability: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Blood Relations, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Directions (Direction Test), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Selection Decision Table (Decision Making), Logical Sequence Of Words, Crypt Arithmetic, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence, TCS NQT Advanced Reasoning Ability
  4. Section A: Arithmetical & Numerical Ability: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Percentage, Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Pipe and Cistern, Mensuration and Geometry, Powers and Exponents (Surds and Indices), Algebra, Probability, Mental Ability, Age Problems, Partnership, Statistics, Arithmetic, Speed Mathematics and Basic Mathematics, Miscellaneous
  5. Section A: English Language & Comprehension: Vocabulary, Subject Verb Agreement (Verb Noun Agreement), Adjectives, Tenses, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Articles, Sentence Construction, Preposition, Direct and Indirect Speech, Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Modals, Active Passive Voice (Voice), Sentence Correction (Error Correction), Adverb, Conjunction, Cloze Test (Cloze Passage)
  6. Section A: Hindi Language & Comprehension: भाषा, लिपि, ध्वनि, वर्ण, अक्षर, स्वर, व्यंजन, मात्रा और संयुक्ताक्षर, वर्तनी, वर्ण-विन्यास, अनुस्वार, अनुनासिक, चंद्रबिंदु और ‘र’ के रूप, शब्द, पद और शब्द-भेद, संज्ञा और सर्वनाम, विशेषण और क्रिया, लिंग, वचन, पुरुष और कारक, काल, वाच्य, वाक्य और वाक्य-भेद, संधि, समास, विलोम शब्द, पर्यायवाची शब्द, सामान्य अशुद्धियाँ, अनेक शब्दों के लिए एक शब्द, मुहावरे और लोकोक्तियाँ, अपठित गद्यांश और अपठित पद्यांश, Multi-Topic Content (Cross-Concept Material), वर्णमाला
  7. Section B: Programming, Data Structures, OOP & Java: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Java, OOPS with C++, Language Design, Intro to Compilers, Visual Basics, Syntax Analysis: Bottom-Up, Object Oriented Technology
  8. Section B: Computer Networks, TCP/IP & Network Security: Introduction to CN, Data Communication, DLL: Flow Control, DLL: Access Control, DLL: Error Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Access Technologies, Network Security, Society, Law & Ethics, Mobile Computing, Net Layer:Routing Protocol, Cyber Safety and Security
  9. Section B: Teaching Methodology: Child Development, Concept of Pedagogy, Theories, Inclusive Education, Experiential Pedagogy, Assessment & Evaluation, Curriculum Framework & Reforms, National Education Policy (NEP) 2020, Psychology, Teaching-Learning Process, Personality Development, Teaching Methods & Strategies, Learning and Motivation, Learners & Learning Process, Factors Affecting Teaching, Methods of Teaching, Nature, Objectives & Characteristics of Teaching, Teaching-Learning Aids & ICT Integration, Classroom Management & Communication, Evaluation, Assessment & Measurement, Curriculum & School Environment, Inclusive Education & Special Needs, Professional Development & Ethics
  10. Section B: Digital Electronics / Boolean Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Analog-Digital Conversion
  11. Section B: Operating Systems & Linux: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, File Management, Disc Scheduling, Unix OS, Linux OS, Distributed Systems, Windows OS
  12. Section B: Data Base Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, File Organization & Indexing, Transaction Management, Concurrency Control, Database Security & Authorization, Database Recovery, Data Warehousing & Mining
  13. Section B: Internet & Web Technologies: Website, Browser & Services, Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, HTML Basics, CSS, Emerging Technologies, JavaScript-Basics, .Net Programming, Electronic Data Interchange and E-Commerce, XML
  14. Section B: Computer Fundamentals, IT Basics & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer, Terms & Abbreviations, MS Office Applications, Instr Formats & Modes, Floating Point Rep, Artificial Intelligence, साइबर सुरक्षा / Cyber Safety and Security, कंप्यूटर सॉफ़्टवेयर / Computer Software, ऑपरेटिंग सिस्टम / Operating System, वर्ड प्रोसेसिंग (MS Word) / Word Processing (MS Word), कंप्यूटर नेटवर्क / Computer Networks
  15. Section B: Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  16. Section B: Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, extras, Fundamentals of Systems and Information Systems
  17. Section B: Design & Analysis of Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  18. Section B: Mathematics: Linear Algebra, Calculus, Trigonometry, Vectors, Set Theory, Functions, Relations, Propositional and Predicate Logic, Research Process Steps, Graph Theory, Number System & Place Value, Factors, Multiples, Divisibility, HCF & LCM, Mensuration — Perimeter, Area, Surface Area, Volume, Data Handling, Graphs & Probability, Coordinates & Graphs, Higher Mathematics — Trigonometry, Quadratics, Polynomials, Progressions, Statistics, Logarithms, समतल क्षेत्रमिति / Plane Mensuration, प्रतिचयन / Sampling
  19. Section B: Computer Graphics, Multimedia & Mobile Computing: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing, Multimedia
  20. Section B: Emerging Trends: Emerging Tech Trends, Knowledge Representation, Natural Language Processing
  21. DSSSB Previous Year Paper:
  22. Business Studies and Management: Business Communication, Business Organization and Management, Financial Accounting, Business Economics, Management Information System (MIS), Knowledge Management & New Economy
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a comprehensive lecture on 'Pipes and Cisterns' problems, a common topic in aptitude tests. The instructor, Yash Jain Sir, begins by defining inlet and outlet pipes, explaining that inflow represents positive work while outflow represents negative work. The core concept of efficiency being inversely proportional to time is introduced, followed by the '1 hour work' method. The lecture heavily features the 'LCM Method' as a shortcut to solve problems involving fractional rates by assuming a total capacity. Various scenarios are covered, including multiple filling pipes, multiple emptying pipes, mixed scenarios with leaks, and problems where pipes are closed at different times. Real exam questions from companies like LTI, Cognizant, Wipro, and GATE are used to demonstrate practical application.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a visual of a pipe filling a bowl, transitioning to a schematic diagram labeled 'PIPES & CISTERNS'. The instructor introduces the topic, pointing out 'INLET PIPES' adding water and 'OUTLET PIPES' removing it. The diagram clearly labels the 'CISTERN' and the flow of water, setting the stage for understanding the physical setup of these problems before moving to abstract concepts.

  2. 2:00 – 5:00 02:00-05:00

    The slide 'BASIC CONCEPTS' appears, defining 'Inflow / Inlet Pipe' as water flowing into the tank and 'Leak / Outflow / Outlet Pipe' as water flowing out. The instructor underlines these definitions and explains that outflow is considered 'negative work'. This section establishes the fundamental terminology and the sign convention used in subsequent calculations, crucial for solving mixed scenarios.

  3. 5:00 – 10:00 05:00-10:00

    The concept of efficiency is introduced with the statement 'Efficiency is inversely proportional to Time'. An example is given: Pipe A fills in 10 mins, Pipe B in 20 mins. Since A is faster, it is more efficient. The rule 'If Efficiency Ratio is a:b, then Time Ratio will be b:a' is highlighted on the slide, providing a quick way to compare work rates without detailed calculations.

  4. 10:00 – 15:00 10:00-15:00

    The '1 hour work' method is explained in detail. If Pipe A fills in 'x' hours, the part filled in 1 hour is 1/x. Similarly, if Pipe B empties in 'y' hours, the part emptied in 1 hour is 1/y. The instructor writes these fractions on the board to illustrate the rate of work, showing how to convert time taken into a work rate per unit time.

  5. 15:00 – 20:00 15:00-20:00

    Formulas for combined work are derived for different cases. Case I involves two inflow pipes (A+B), Case II involves one inflow and one outflow (A-B), and Case III involves two outflow pipes. The instructor writes the general formulas for these scenarios on the whiteboard, showing how to combine the individual rates to find the net rate of work for the system.

  6. 20:00 – 25:00 20:00-25:00

    A problem is solved using the LCM method. Pipes A and B fill a tank in 36 and 45 hours. The LCM of 36 and 45 is calculated as 180 litres, representing the total capacity. The rates are calculated as 5 litres/hr and 4 litres/hr respectively. This method avoids fractions and simplifies the arithmetic involved in finding the combined work rate.

  7. 25:00 – 30:00 25:00-30:00

    The instructor solves the previous problem by adding the rates (5+4=9 litres/hr). The total time is calculated as Total Capacity / Combined Rate = 180 / 9 = 20 hours. The formula (xy)/(x+y) is also shown as an alternative method for two pipes filling a tank, reinforcing the connection between the LCM method and standard formulas.

  8. 30:00 – 35:00 30:00-35:00

    A problem involving two pipes emptying a tank is presented. Pipe A empties in 10 hours, Pipe B in 5 hours. The instructor applies the formula for two outflow pipes, which is similar to the filling formula but results in a faster emptying time. This demonstrates that the mathematical structure remains consistent regardless of whether the pipes are filling or emptying.

  9. 35:00 – 40:00 35:00-40:00

    A problem with three pipes filling a tank is solved. Pipes A, B, and C fill in 6, 10, and 12 hours. The LCM is 60 litres. Rates are 10, 6, and 5 litres/hr. The combined rate is 21 litres/hr. The time to fill the tank is calculated as 60/21 = 20/7 hours. The formula for three pipes (xyz)/(xy+yz+zx) is written on the board as a shortcut.

  10. 40:00 – 45:00 40:00-45:00

    A problem with two filling pipes and one emptying pipe is discussed. Pipes fill in 10 and 16 hours, while a third empties in 32 hours. The LCM is 160 litres. Rates are 16, 10, and -5 litres/hr. The instructor emphasizes the importance of assigning negative signs to emptying pipes to correctly calculate the net rate of work.

  11. 45:00 – 50:00 45:00-50:00

    A leak problem is introduced. Tap A fills in 12 hours, but with a leak, it takes 15 hours. The instructor calculates the leak's rate by finding the difference in efficiency between the tap alone and the tap with the leak. This scenario highlights how external factors like leaks affect the overall time taken to complete a task.

  12. 50:00 – 55:00 50:00-55:00

    A GATE 2014 problem is solved. It takes 30 minutes to empty a half tank. The goal is to fill the full tank in 10 minutes while simultaneously pumping water in. The draining rate is calculated first. The instructor breaks down the problem into rates per minute to find the required pumping rate relative to the draining rate.

  13. 55:00 – 60:00 55:00-60:00

    The draining rate is found to be 1/60 of the tank per minute (since half tank in 30 mins means full tank in 60 mins). To fill the full tank in 10 mins, the net rate must be 1/10. The pumping rate is calculated to be 3 times the draining rate. This example shows how to handle problems with simultaneous inflow and outflow.

  14. 60:00 – 65:00 60:00-65:00

    A problem where Pipe B is closed after some time is discussed. Pipes A and B fill in 24 and 32 minutes. The tank is filled in 18 minutes. The instructor sets up the equation 18/24 + p/32 = 1 to find the time 'p' Pipe B was open. This introduces the concept of partial work done by different pipes.

  15. 65:00 – 70:00 65:00-70:00

    The instructor solves the pipe closed problem. Pipe A works for the full 18 minutes, contributing 18/24 of the work. The remaining work is done by Pipe B. The equation 18/24 + p/32 = 1 is solved to find p=8 mins. This demonstrates how to calculate the time a specific pipe needs to work to complete the remaining portion of the task.

  16. 70:00 – 72:11 70:00-72:11

    The video concludes with the final answer to the last problem, reinforcing the method used. The instructor summarizes the key takeaways from the lecture, emphasizing the LCM method and the importance of sign conventions for inflow and outflow. The Knowledge Gate logo appears, marking the end of the session.

The lecture systematically builds understanding from basic definitions to complex problem-solving techniques. It starts by defining inlet and outlet pipes and establishing the relationship between efficiency and time. The '1 hour work' method is introduced as a foundational concept, leading to the derivation of formulas for combined work. The 'LCM Method' is presented as a powerful shortcut to handle fractional rates by assuming a total capacity. Various scenarios are covered, including multiple filling pipes, multiple emptying pipes, mixed scenarios with leaks, and problems where pipes are closed at different times. The instructor uses real exam questions from companies like LTI, Cognizant, Wipro, and GATE to demonstrate practical application. The video emphasizes visualizing the problem, assigning rates, and using algebraic equations to find the solution.

Loading lesson…