Finding ratio of 2 numbers from their sum & difference

Duration: 3 min

This video lesson is available to enrolled students.

Return to /learn/RSSB-BASIC-COMPUTER-INSTRUCTOR/paper-1-basic-numeracy/ratio-and-proportion-ratios/division-of-quantity-in-a-given-ratio/asset-finding-ratio-of-2-numbers-from-their-sum-difference after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About the Course: About the Course
  2. Paper-1 & 2 | Basic Numeracy / आधारभूत संख्यात्मक योग्यता: Ratio and Proportion / अनुपात और समानुपात, Divisibility Rules / विभाज्यता के नियम, Mixture and Alligation / मिश्रण और एलिगेशन, Permutation and Combination / क्रमचय और संचय, Logarithm / लघुगणक, Number System / संख्या पद्धति, HCF and LCM / महत्तम समापवर्तक और लघुत्तम समापवर्त्य, Sequences, Series and Combinatorics / अनुक्रम, श्रेणी और संयोजन, Time, Speed and Distance / समय, चाल और दूरी, Percentage / प्रतिशत, Average / औसत, Solid Mensuration / घन क्षेत्रमिति, Age Problems / आयु संबंधी प्रश्न, Arithmetic / अंकगणित, Statistics / सांख्यिकी, Probability / प्रायिकता, Profit, Loss and Discount / लाभ, हानि और बट्टा, Simple and Compound Interest / साधारण और चक्रवृद्धि ब्याज, Partnership / साझेदारी, Speed Mathematics and Basic Mathematics / द्रुत गणित और आधारभूत गणित, Algebra / बीजगणित, Simplification, Indices and Surds / सरलीकरण, घातांक और करणी, Time and Work / समय और कार्य, Pipe and Cistern / नल और टंकी, RSSB Specific Videos - Basic Numeracy / RSSB विशेष वीडियो - आधारभूत संख्यात्मक योग्यता, Sets, Relations, Functions and Discrete Mathematics / समुच्चय, संबंध, फलन और विविक्त गणित, Number Systems and Number Theory / संख्या पद्धति और संख्या सिद्धांत, Coordinate Geometry, Vectors and 3D Geometry / निर्देशांक ज्यामिति, सदिश और त्रिविमीय ज्यामिति, Polynomials, Equations and Complex Numbers / बहुपद, समीकरण और सम्मिश्र संख्याएँ
  3. Paper-1 & 2 | Data Interpretation / आँकड़ों की व्याख्या: Data Interpretation / आँकड़ा निर्वचन
  4. Paper-1 & 2 | General Mental Ability / सामान्य मानसिक योग्यता: Mental Ability / मानसिक योग्यता, RSSB Specific Videos - Mental Ability / RSSB विशेष वीडियो - मानसिक योग्यता
  5. Paper-1 & 2 | Logical Reasoning and Analytical Ability / तार्किक तर्कणा एवं विश्लेषणात्मक क्षमता: Series / श्रेणी, Coding-Decoding / कूट लेखन एवं कूट वाचन, Data Sufficiency / आँकड़ों की पर्याप्तता, Non-Verbal Reasoning / अशाब्दिक तर्क, Syllogisms / न्यायवाक्य, Seating Arrangement and Puzzles / बैठक व्यवस्था एवं पहेलियाँ, Blood Relations / रक्त संबंध, Direction and Distance / दिशा एवं दूरी, Analytical Reasoning (Counting Figures Reasoning) / विश्लेषणात्मक तर्क (आकृति गणना तर्क), Mathematical Operations and Missing Numbers / गणितीय संक्रियाएँ एवं लुप्त संख्या, Calendar and Clock / कैलेंडर एवं घड़ी, Clock / घड़ी, Cubes, Dice and Figure Counting / घन, पासा एवं आकृतियों की गिनती, Venn Diagrams, Syllogism and Inequalities / वेन आरेख, न्याय वाक्य एवं असमानता, Analogy and Classification / सादृश्यता एवं वर्गीकरण, Order and Ranking / क्रम एवं रैंकिंग, Statement-Based Reasoning / कथन आधारित तार्किक विवेचन, Data Arrangement / आँकड़ों की व्यवस्था, Alphabet and Number Test / वर्णमाला एवं संख्या परीक्षण, Crypt Arithmetic / कूट अंकगणित
  6. Paper-1 & 2 | Decision Making and Problem Solving / निर्णय लेना एवं समस्या समाधान: Data Sufficiency and Decision Making / आँकड़ों की पर्याप्तता एवं निर्णय क्षमता
  7. Paper-1 | General Science / सामान्य विज्ञान: Scientific Achievements and Research / वैज्ञानिक उपलब्धियाँ और अनुसंधान, Biology / जीव विज्ञान, Chemistry / रसायन विज्ञान, RSSB Specific Videos / RSSB विशेष वीडियो
  8. Paper-1 | General Awareness / सामान्य जागरूकता: State-Specific General Knowledge / राज्य विशेष सामान्य ज्ञान, Current Affairs / समसामयिकी
  9. Paper - 2 | Digital Logic Systems: Digital Systems & Boolean Basics, Logic Gates & Hardware, Combinational Circuit, Sequential Circuits
  10. Paper-2 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Calculus, Relational Algebra, SQL, NoSQL
  11. Paper-2 | Data Structures & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Algorithm Analysis, Sorting Algorithms, Intro to Compilers, Hashing
  12. Paper 2 | Data Communication and Network Security: Introduction to CN, Data Communication, Data Link Layer - Ethernet, DLL: Error Control, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Application Layer, Hardware basics, Network Security, Ethical Hacking
  13. Paper-2 | Operating Systems: Introduction to OS, Process Management, Memory Management, File Management, Deadlock
  14. Paper-2 | Computer Organization and Architecture: 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, Number System, Number Representation
  15. Paper 2 | System Analysis and Design: Fundamentals of Systems and Information Systems, Fundamentals of Software Engineering, SDLC and Development Approaches, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Security, Risk Management & Maintenance, Software Testing
  16. Paper-2 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  17. Paper 2 | OOPS , C++ , JAVA: Language Design, OOPS with C++, Java, .Net Programming, Java Fundamentals
  18. 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
  19. Emerging Trends and AI: Emerging Tech Trends, Computer Fundamentals, Trade, Marketing and Consumer Protection / व्यापार, विपणन एवं उपभोक्ता संरक्षण, Internet of Things, Cloud Computing
  20. Paper-2 | Data Processing (Ms-Office): MS Office Applications, Computer Software, Operating System, Word Processing (MS Word), Presentation Software (MS PowerPoint)
  21. Paper-2 | Internet and Web Technologies: HTML Basics, CSS, XML, JavaScript-Basics, Internet Fundamentals, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, Terms & Abbreviations, Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Cyber Safety and Security, Computer Networks
  22. Paper 2 | Pedagogy / शिक्षाशास्त्र: Growth and Development / वृद्धि और विकास, Theories of Development / विकास के सिद्धांत, Concept of Pedagogy / शिक्षाशास्त्र की संकल्पना, Inclusive Education / समावेशी शिक्षा, Experiential Pedagogy / अनुभवात्मक शिक्षाशास्त्र, Assessment and Evaluation / आकलन और मूल्यांकन, Cognitive Processes / संज्ञानात्मक प्रक्रियाएँ, Socialisation and Gender / समाजीकरण और जेंडर, National Education Policy (NEP) 2020 / राष्ट्रीय शिक्षा नीति (NEP) 2020
  23. Live Classes: RSSB Live Sessions
  24. Paper 1 - Full Mock Tests:
  25. Paper 2 - Full Mock Tests:
  26. BCI Previous Year Papers:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This short math lesson teaches how to find the ratio of two numbers when given the ratio of their sum and difference. The instructor introduces variables a and b, sets up (a+b)/(a-b) = given ratio, then solves the example where sum:diff = 9:2. Cross-multiplication gives 2(a+b) = 9(a-b), leading to 11b = 7a and a/b = 11/7. A shortcut formula a/b = (9+2)/(9-2) confirms the result 11:7. The video ends with a thanks screen.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The lesson opens with the title 'Finding Ratio of Numbers Given Ratio of Sum & Difference'. The instructor defines two numbers as a and b, writes 'a, b = x ?', and establishes the core relationship (a+b)/(a-b) = given ratio, with a circled 'a/b' indicating the target. The example question appears: 'Ratio of sum & difference of two numbers is 9 : 2. Find the ratio of numbers.' The instructor writes 'Sum/Diff = 9/2' and begins forming the equation (a+b)/(a-b) = 9/2, setting up the algebraic method.

  2. 2:00 – 3:11 02:00-03:11

    The instructor solves the equation by cross-multiplying: 2(a+b) = 9(a-b). Expanding and simplifying yields 11b = 7a, so a/b = 11/7. A shortcut formula is then shown: a/b = (9+2)/(9-2) = 11/7, confirming the ratio of numbers is 11:7. The video concludes with a closing screen displaying 'THANKS FOR WATCHING' in bold text on a black background, with an orange highlight box around 'THANKS' and an underline beneath the message.

The central concept is deriving a/b from (a+b)/(a-b) = m/n. The standard method uses cross-multiplication: n(a+b) = m(a-b), which simplifies to (m-n)a = (m+n)b, giving a/b = (m+n)/(m-n). For the example m=9, n=2: a/b = 11/7. The shortcut formula directly applies this result. Key teaching cues include variable setup, cross-multiplication to eliminate fractions, and verification via the shortcut. The lesson is concise and focused on one problem type with a clear worked example.

Loading lesson…