Part 7 - Important Practice Question

Duration: 8 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. Paper-1 & 2 | Basic Numeracy: अनुपात और समानुपात / Ratio and Proportion, Divisibility Rules, मिश्रण और एलिगेशन / Mixture and Alligation, Permutation and Combination, Logarithm, संख्या पद्धति / Number System, महत्तम समापवर्तक और लघुत्तम समापवर्त्य / HCF and LCM, Sequence and Series (Series), समय, चाल और दूरी / Time, Speed and Distance, प्रतिशत / Percentage, औसत / Average, घन क्षेत्रमिति / Solid Mensuration, Age Problems, Arithmetic, Statistics, Probability, लाभ, हानि और बट्टा / Profit, Loss and Discount, साधारण और चक्रवृद्धि ब्याज / Simple and Compound Interest, Partnership, Speed Mathematics and Basic Mathematics, Algebra, सरलीकरण, घातांक और करणी / Simplification, Indices and Surds, समय और कार्य / Time and Work, Pipe and Cistern, RSSB Specific Videos - Basic Numeracy, 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. Paper-1 & 2 | Data Interpretation: आँकड़ा निर्वचन / Data Interpretation
  4. Paper-1 & 2 | General Mental Ability: Mental Ability, RSSB Specific Videos - Mental Ability
  5. Paper-1 & 2 | Logical Reasoning and Analytical Ability: श्रेणी / Series, कूट लेखन एवं कूट वाचन / Coding-Decoding, Data Sufficiency, अशाब्दिक तर्क / Non-Verbal Reasoning, Syllogisms, बैठक व्यवस्था एवं पहेलियाँ / Seating Arrangement and Puzzles, रक्त संबंध / Blood Relations, दिशा एवं दूरी / Direction and Distance, Analytical Reasoning (Counting Figures Reasoning), गणितीय संक्रियाएँ एवं लुप्त संख्या / Mathematical Operations and Missing Numbers, कैलेंडर एवं घड़ी / Calendar and Clock, Clock, घन, पासा एवं आकृतियों की गिनती / Cubes, Dice and Figure Counting, वेन आरेख, न्याय वाक्य एवं असमानता / Venn Diagrams, Syllogism and Inequalities, सादृश्यता एवं वर्गीकरण / Analogy and Classification, क्रम एवं रैंकिंग / Order and Ranking, कथन आधारित तार्किक विवेचन / Statement-Based Reasoning, Data Arrangement, वर्णमाला एवं संख्या परीक्षण / Alphabet and Number Test, Crypt Arithmetic
  6. Paper-1 & 2 | Decision Making and Problem Solving: आँकड़ों की पर्याप्तता एवं निर्णय क्षमता / Data Sufficiency and Decision Making
  7. Paper-1 | General Science: वैज्ञानिक उपलब्धियाँ और अनुसंधान / Scientific Achievements and Research, Biology, Chemistry, RSSB Specific Videos
  8. Paper-1 | General Awareness: राज्य विशेष सामान्य ज्ञान / State-Specific General Knowledge, समसामयिकी / Current Affairs
  9. Paper-2 | Fundamentals of Computer: Basics of COA, Number System, Floating Point Rep, Number Representation
  10. Paper - 2 | Digital Logic Systems: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits
  11. Paper-2 | Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Linux OS, Distributed Systems
  12. Paper-2 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Relational Calculus, File Organization & Indexing, Transaction Management, Concurrency Control
  13. Paper-2 | Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  14. Paper-2 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  15. Paper 2 | Oops, C++, Java: Language Design, OOPS with C++, Java, .Net Programming, Java Fundamentals
  16. Paper 2 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  17. Paper 2 | Emerging Trends and AI: Emerging Tech Trends, कंप्यूटर के मूल सिद्धांत / Computer Fundamentals, व्यापार, विपणन एवं उपभोक्ता संरक्षण / Trade, Marketing and Consumer Protection, कंप्यूटर नेटवर्क / Computer Networks
  18. Paper-2 | Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Advanced Algorithms
  19. Paper 2 | Data Communication and Network Security: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security, Ethical Hacking
  20. Paper-2 I Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  21. Paper-2 | Computer Organization and Architecture: Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations
  22. Paper-2 | Web Development: JavaScript-Basics, HTML Basics, CSS, XML
  23. Pedagogy: वृद्धि और विकास / Growth and Development, Concept of Pedagogy, संज्ञानात्मक प्रक्रियाएँ / Cognitive Processes, विकास के सिद्धांत / Theories of Development, समावेशी शिक्षा / Inclusive Education, Experiential Pedagogy, समाजीकरण और जेंडर / Socialisation and Gender, National Education Policy (NEP) 2020
  24. Live Sessions: RSSB Live Sessions
  25. RSSB Paper 1 - Full Mock Tests:
  26. RSSB Paper 2 - Full Mock Tests:
  27. SCI Previous Year Papers:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This video is a lecture on data sufficiency, a common question type in standardized tests like the GATE. The instructor, Yash Jain Sir, introduces the concept using a problem where the goal is to find the value of X given that X and Y are distinct integers and their product is 30. The problem presents two statements: Statement 1 (X is odd) and Statement 2 (X > Y). The lecture systematically analyzes the sufficiency of each statement individually and then together, using a methodical approach of listing all possible integer pairs (x, y) that satisfy xy = 30. The instructor demonstrates that Statement 1 alone is not sufficient because it allows for multiple values of X (e.g., 1, 3, 5, 15, -1, -3, -5, -15). Statement 2 alone is also not sufficient as it allows for multiple values (e.g., 15, 10, 6, 5, 3, 2, -1, -2, -3, -5, -6, -10, -15). However, when both statements are considered together, the only pair that satisfies both conditions (X is odd and X > Y) is (15, 2), which uniquely determines X as 15. The video concludes that both statements together are sufficient to answer the question, which is the correct answer choice for this type of problem.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a title slide for a 'DATA SUFFICIENCY' lesson, featuring a futuristic cityscape. It then transitions to a second slide with the title 'Questions' and motivational text about practice. The main content begins with a problem statement on a whiteboard: 'Que: What is the value of X, if X and Y are two distinct integers and their product is 30?'. Below this, two statements are listed: 'Statement 1: X is odd' and 'Statement 2: X > Y'. The instructor, Yash Jain Sir, is visible in a small window. The multiple-choice options are presented: (a) Statement I alone is sufficient, (b) Statement II alone is sufficient, (c) Both statements put together are sufficient, (d) Either of the statements individually is sufficient, (e) Both statements put are not sufficient.

  2. 2:00 – 5:00 02:00-05:00

    The instructor begins to solve the problem by analyzing Statement 1: 'X is odd'. He writes the condition 'xy = 30' and starts listing the possible integer pairs (x, y) that satisfy this equation. He systematically lists the positive factor pairs: (1, 30), (2, 15), (3, 10), (5, 6), (6, 5), (10, 3), (15, 2), (30, 1). He then considers the negative pairs: (-1, -30), (-2, -15), (-3, -10), (-5, -6), (-6, -5), (-10, -3), (-15, -2), (-30, -1). He then applies the condition from Statement 1, 'X is odd', to filter the list. The possible values for X are {1, 3, 5, 15, -1, -3, -5, -15}. Since there are multiple possible values for X, he concludes that Statement 1 alone is not sufficient to determine a unique value for X.

  3. 5:00 – 7:37 05:00-07:37

    The instructor now analyzes Statement 2: 'X > Y'. He reviews the list of all possible integer pairs (x, y) where xy = 30. He applies the condition X > Y to each pair. For example, (15, 2) satisfies 15 > 2, but (2, 15) does not. He identifies all pairs where X > Y, which include (15, 2), (10, 3), (6, 5), (5, 6), (3, 10), (2, 15), (1, 30), (-1, -30), (-2, -15), (-3, -10), (-5, -6), (-6, -5), (-10, -3), (-15, -2), (-30, -1). The possible values for X are {15, 10, 6, 5, 3, 2, 1, -1, -2, -3, -5, -6, -10, -15, -30}. Since there are multiple possible values for X, he concludes that Statement 2 alone is not sufficient. Finally, he combines both statements. He takes the list of X values from Statement 1 ({1, 3, 5, 15, -1, -3, -5, -15}) and the list from Statement 2 ({15, 10, 6, 5, 3, 2, 1, -1, -2, -3, -5, -6, -10, -15, -30}) and finds their intersection. The common values are {1, 3, 5, 15, -1, -3, -5, -15}. He then checks which of these values satisfy X > Y. For X=15, Y=2, 15>2 is true. For X=5, Y=6, 5>6 is false. For X=3, Y=10, 3>10 is false. For X=1, Y=30, 1>30 is false. For negative values, X=-1, Y=-30, -1>-30 is true, but X=-3, Y=-10, -3>-10 is true, and so on. He realizes he needs to check the actual pairs. He identifies that the only pair that satisfies both conditions is (15, 2). Therefore, X=15 is the only possible value. He concludes that both statements together are sufficient to answer the question, and the correct answer is (c). The video ends with a 'THANKS FOR WATCHING' screen.

The video provides a clear, step-by-step demonstration of how to solve a data sufficiency problem. It emphasizes the importance of considering all possible cases, especially when dealing with integers and inequalities. The core method involves listing all potential solutions to the main condition (xy=30) and then applying the constraints from each statement to narrow down the possibilities. The key insight is that a statement is sufficient only if it leads to a unique answer. The instructor effectively shows that while neither statement alone is sufficient, their combination is, which is a common pattern in such questions. The visual aid of writing on the board helps to organize the thought process and makes the logic transparent for the student.

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