Person joining or leaving in between

Duration: 12 min

This video lesson is available to enrolled students.

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Inside: a video lesson and guided study material.

Module outline

  1. About the course: About the Course
  2. Mathematical Aptitude: संख्या पद्धति / Number System, महत्तम समापवर्तक और लघुत्तम समापवर्त्य / HCF and LCM, Divisibility Rules, प्रतिशत / Percentage, अनुपात और समानुपात / Ratio and Proportion, औसत / Average, लाभ, हानि और बट्टा / Profit, Loss and Discount, समय और कार्य / Time and Work, घन क्षेत्रमिति / Solid Mensuration, साधारण और चक्रवृद्धि ब्याज / Simple and Compound Interest, समय, चाल और दूरी / Time, Speed and Distance, Age Problems, मिश्रण और एलिगेशन / Mixture and Alligation, Algebra, सरलीकरण, घातांक और करणी / Simplification, Indices and Surds, Pipe and Cistern, Trigonometry, Statistics, आँकड़ा निर्वचन / Data Interpretation, Arithmetic, समुच्चय, संबंध, फलन और विविक्त गणित / Sets, Relations, Functions and Discrete Mathematics, संख्या पद्धति और संख्या सिद्धांत / Number Systems and Number Theory, निर्देशांक ज्यामिति, सदिश और त्रिविमीय ज्यामिति / Coordinate Geometry, Vectors and 3D Geometry, बहुपद, समीकरण और सम्मिश्र संख्याएँ / Polynomials, Equations and Complex Numbers
  3. Logical Reasoning: श्रेणी / Series, कूट लेखन एवं कूट वाचन / Coding-Decoding, सादृश्यता एवं वर्गीकरण / Analogy and Classification, रक्त संबंध / Blood Relations, दिशा एवं दूरी / Direction and Distance, क्रम एवं रैंकिंग / Order and Ranking, अशाब्दिक तर्क / Non-Verbal Reasoning, बैठक व्यवस्था एवं पहेलियाँ / Seating Arrangement and Puzzles, Syllogisms, वेन आरेख, न्याय वाक्य एवं असमानता / Venn Diagrams, Syllogism and Inequalities, गणितीय संक्रियाएँ एवं लुप्त संख्या / Mathematical Operations and Missing Numbers, वर्णमाला एवं संख्या परीक्षण / Alphabet and Number Test, कथन आधारित तार्किक विवेचन / Statement-Based Reasoning, Analytical Reasoning (Counting Figures Reasoning), घन, पासा एवं आकृतियों की गिनती / Cubes, Dice and Figure Counting, कैलेंडर एवं घड़ी / Calendar and Clock, Clock
  4. General Knowledge: वैज्ञानिक उपलब्धियाँ और अनुसंधान / Scientific Achievements and Research, Chemistry, Biology, History, Geography, Polity, Indian Economy, समसामयिकी / Current Affairs, Static General Knowledge
  5. Art of Teaching: शिक्षण-अधिगम प्रक्रिया एवं कक्षा प्रबंधन / Teaching-Learning Process and Classroom Management, Learners & Learning Process, Factors Affecting Teaching, शिक्षण विधियाँ एवं उपागम / Teaching Methods and Approaches, सूक्ष्म शिक्षण एवं कक्षा संप्रेषण / Microteaching and Classroom Communication, शिक्षण सहायक सामग्री एवं शैक्षिक तकनीकी / Teaching Aids and Educational Technology, आकलन एवं मूल्यांकन / Assessment and Evaluation, शिक्षक: गुण, व्यावसायिक नैतिकता एवं विकास / Teacher: Qualities, Professional Ethics and Development, शैक्षिक नीतियाँ, अधिनियम एवं प्रशासन / Educational Policies, Acts and Administration, पाठ्यचर्या, कला एवं सह-शैक्षिक क्षेत्र / Curriculum, Arts and Co-curricular Areas, निर्देशन एवं परामर्श / Guidance and Counselling, दिव्यांग बच्चों की शिक्षा / Education of Children with Disabilities, Micro-Teaching & Teaching Skills, पाठ योजना / Lesson Planning
  6. Environmental Science: Environment
  7. Unit 1 | Digital Electronics: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  8. Unit 2 | COA: Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations, Programming the Basic Computer
  9. Unit 3 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  10. Unit 3 | Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  11. Unit 4 | Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  12. Unit 5 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management
  13. Unit 6 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Transaction Management, Concurrency Control
  14. Unit 7 | Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer
  15. Unit 8 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  16. Unit 9 | Object Oriented Programming: OOPS with C++
  17. Unit 10 | Web Development: HTML Basics, CSS, JavaScript-Basics, XML, Node.js
  18. Unit 11 | Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines
  19. Unit 12 | IoT: Emerging Tech Trends, Cloud Computing, कंप्यूटर नेटवर्क / Computer Networks
  20. Unit 13 | Artificial Intelligence: Approaches to AI, Search Algorithms, Game Playing, Knowledge Representation, Natural Language Processing, Artificial Neural Networks, Genetic Algorithms
  21. Unit 14 | E-Commerce: Electronic Data Interchange and E-Commerce, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Physical Security and Cryptography Basics, Cyber Safety and Security
  22. Unit 15 | Multimedia: Multimedia
  23. Unit 16 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis, DSA using Python
  24. Full Length Mock Tests — General Paper:
  25. Full Length Mock Tests — Computer Science (Paper II):
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video is a lecture on solving time and work problems, a common topic in competitive exams. The instructor, Yash Jain Sir, presents a series of four problems, each with a different scenario involving multiple workers. The core concept taught is that the total work done is the sum of the work done by each individual, which is calculated as (Time Worked / Time to Complete Alone). The video demonstrates a systematic approach: first, defining variables for the time each person takes to complete the work alone, then setting up an equation where the sum of the fractions of work completed by each person equals 1 (the whole work). The first problem involves two people working together for a period before one leaves. The second problem features three people with staggered start and end times. The third problem uses the combined work rates of pairs to find an individual's rate. The fourth problem uses the LCM method to simplify calculations. The instructor uses a digital whiteboard to write out the equations and solve them step-by-step, providing a clear, methodical guide for students.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a title card featuring the text 'TIME & WORK' and an illustration of a person working at a computer. It then transitions to a lecture slide for Question 1. The problem states that Gangadhar and Shaktimaan can complete a work in 18 and 24 days respectively. They work together for 8 days, after which Gangadhar leaves, and Shaktimaan finishes the remaining work. The question asks for the number of days Shaktimaan took to finish the remaining work. The instructor, Yash Jain Sir, is visible in a small window in the bottom right corner. The slide also shows the answer as '16/3 days' and the source as 'COGNIZANT 2018'. The instructor begins to explain the problem, setting up the scenario and introducing the concept of work rates.

  2. 2:00 – 5:00 02:00-05:00

    The instructor explains the general formula for time and work problems. He writes on the digital board: 'Time Worked by A / A's alone time + Time Worked by B / B's alone time = 1'. He then applies this to the first problem, defining 'A' as Gangadhar (18 days) and 'B' as Shaktimaan (24 days). He writes the equation: '8/18 + x/24 = 1', where 'x' is the number of days Shaktimaan worked alone. He proceeds to solve the equation step-by-step, first simplifying 8/18 to 4/9, then finding a common denominator of 72, and finally solving for 'x' to get 16/3 days. The instructor emphasizes that the sum of the work done by each person must equal the total work, which is 1.

  3. 5:00 – 10:00 05:00-10:00

    The video transitions to Question 2. The problem states that Ajay, Vijay, and Sujoy can complete a work in 10, 12, and 15 days respectively. They all start together, Ajay leaves after 2 days, and Vijay leaves 3 days before the work is completed. The question asks for the total time taken to complete the work. The instructor sets up the equation: '2/10 + (x-3)/12 + x/15 = 1', where 'x' is the total time. He explains that Ajay worked for 2 days, Vijay worked for (x-3) days, and Sujoy worked for the full 'x' days. He then solves the equation by finding a common denominator of 60, simplifying to '12 + 5(x-3) + 4x = 60', and solving for 'x' to get 7 days. The instructor then moves to Question 3, which states that A and B together can do a work in 12 days, and B and C together can do it in 16 days. After A works for 5 days, B for 7 days, and C for 13 days, the work is completed. The question asks for the number of days C alone would take to finish the work. The instructor sets up the equation: '5/12 + 7/16 + 13/x = 1'.

  4. 10:00 – 11:47 10:00-11:47

    The instructor continues solving Question 3. He simplifies the equation '5/12 + 7/16 + 13/x = 1' by finding a common denominator of 48, which gives '20/48 + 21/48 + 13/x = 1'. This simplifies to '41/48 + 13/x = 1'. He then isolates the term with 'x': '13/x = 1 - 41/48 = 7/48'. Solving for 'x' gives 'x = (13 * 48) / 7', which is approximately 88.57, but the instructor notes this is not among the options. He then re-examines the problem and realizes the work done by A and B is not independent. He corrects the approach by using the combined rates: (A+B)'s 5-day work + (B+C)'s 2-day work + C's 11-day work = 1. He writes the equation: '5/12 + 2/16 + 11/x = 1'. He solves this, finding a common denominator of 48, which gives '20/48 + 6/48 + 11/x = 1', or '26/48 + 11/x = 1'. This simplifies to '11/x = 22/48', and solving for 'x' gives 24 days. The video then moves to Question 4, which involves Hari and Giri working together, with Hari leaving after some days and Giri finishing the remaining work in 47 days. The instructor sets up the equation using the LCM method: 'x/70 + (x+47)/60 = 1'. The video ends with a 'THANKS FOR WATCHING' screen.

The video provides a comprehensive tutorial on solving time and work problems by breaking them down into a systematic process. The central theme is the application of the formula: (Time Worked / Time to Complete Alone) = Fraction of Work Done. The instructor demonstrates this principle across four distinct problem types: two individuals working together and one leaving, three individuals with staggered work periods, using combined work rates to find an individual's rate, and using the LCM method for efficient calculation. The progression from simple to more complex problems, coupled with clear, step-by-step algebraic solutions, equips students with a robust methodology for tackling a wide range of time and work questions in competitive exams.

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