Average - Short Tricks to Find Average Speed

Duration: 7 min

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Module outline

  1. About the Course: About the Course
  2. Paper-1 & 2 | Basic Numeracy: Ratio and Proportion (Ratios), Divisibility Rules, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Percentage, Average, Mensuration and Geometry, Age Problems, Arithmetic, Statistics, Probability, Profit and Loss, Simple Interest and Compound Interest, Partnership, Speed Mathematics and Basic Mathematics, Algebra, Powers and Exponents (Surds and Indices), Time and Work, Pipe and Cistern, RSSB Specific Videos - Basic Numeracy
  3. Paper-1 & 2 | Data Interpretation: 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: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Syllogisms, Seating Arrangements, Blood Relations, Directions (Direction Test), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Venn Diagram, Analogy, Ranking, Order and Sequence, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Data Arrangement, Logical Sequence Of Words, Crypt Arithmetic
  6. Paper-1 & 2 | Decision Making and Problem Solving: Selection Decision Table (Decision Making)
  7. Paper-1 | General Science: Physics, Biology, Chemistry, RSSB Specific Videos
  8. Paper-1 | General Awareness: State Wise GK, GK- Current Affairs
  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, Artificial Intelligence
  20. Paper-2 | Data Processing (Ms-Office): MS Office Applications
  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
  22. Paper 2 | Pedagogy: Child Development, Theories, Concept of Pedagogy, Inclusive Education, Experiential Pedagogy, Assessment & Evaluation, Psychology, Curriculum Framework & Reforms, National Education Policy (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 educational video is a tutorial on calculating average speed for different scenarios, presented by an instructor in a split-screen format. The video begins with a title card and then introduces a problem where a 'Corona Virus' travels from Mumbai to Delhi at 40 km/hr and returns at 60 km/hr, asking for the average speed. The instructor, Yash Jain, explains the fundamental formula for average speed: total distance divided by total time. He demonstrates the solution by assuming a distance 'x' for the one-way trip, calculating the time for each leg (x/40 and x/60), summing them to get total time, and then dividing the total distance (2x) by the total time to find the average speed, which is 48 km/hr. The video then transitions to a second problem involving multiple segments with different distances and speeds, and finally, it presents a general formula for average speed when the distance for each segment is equal, which is 2*S1*S2/(S1+S2). The video concludes with a summary of the key formulas and a 'Thanks for Watching' screen.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a title card displaying the word 'AVERAGE' in a futuristic, glowing font against a dark, digital background. It then transitions to a split-screen view of a lecture. The main screen is a blackboard with a question written in yellow: 'Q1: Corona Virus goes from Mumbai to Delhi at the speed of 40 km/hr and returns back to Mumbai at 60 km/hr. Find the average speed in km/hr?'. The options are (a) 50, (b) 48, (c) 52, (d) Data Insufficient. A small yellow sticky note with the word 'Important' is visible. The instructor, Yash Jain, appears in a small window at the bottom right, introducing the topic. He states that a trick to solve this question in 20 seconds will be discussed at the end of the video.

  2. 2:00 – 5:00 02:00-05:00

    The instructor begins solving the first problem on the blackboard. He writes the fundamental formula for average speed: 'Avg Speed = Total distance / Total time'. He then sets up the problem by letting the distance from Mumbai to Delhi be 'x'. He writes the time for the first leg as 'x/40' and for the return leg as 'x/60'. He calculates the total time as 'x/40 + x/60' and the total distance as '2x'. He then substitutes these into the average speed formula, resulting in '2x / (x/40 + x/60)'. He simplifies this expression by factoring out 'x' from the denominator, leading to '2 / (1/40 + 1/60)'. He then calculates the sum in the denominator as '100/2400' or '1/24', and finally, the average speed as '2 / (1/24) = 48 km/hr'. He confirms that the correct answer is (b) 48.

  3. 5:00 – 7:00 05:00-07:00

    The video transitions to a second problem, Q2, which involves multiple segments: 10 km at 5 km/hr, 30 km at 6 km/hr, and 20 km at 10 km/hr. The instructor explains that this is a case where distances are not equal. He then introduces a general formula for average speed when the distance for each segment is equal, which is '2*S1*S2 / (S1+S2)'. He writes this formula on the board and then shows how it applies to the first problem, with S1=40 and S2=60, resulting in '2*40*60 / (40+60) = 4800/100 = 48 km/hr'. He then briefly mentions that for more than two segments with equal distance, the formula is '3*S1*S2*S3 / (S1*S2 + S2*S3 + S1*S3)'. The video ends with a 'Thanks for Watching' screen.

The video provides a clear, step-by-step tutorial on calculating average speed, starting with a specific problem and then generalizing the solution. It effectively teaches the core concept that average speed is total distance over total time, and then demonstrates how to apply this to a round trip with different speeds. The instructor uses a consistent method of setting up variables and simplifying equations, which is a valuable problem-solving technique. The video also introduces a key shortcut formula for equal-distance trips, making it a comprehensive resource for students preparing for competitive exams.

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