Case 4_ Two Trains Crossing One Other (Same Direction)

Duration: 13 min

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Inside: a video lesson and guided study material.

Module outline

  1. About the Course: About the Course
  2. Section 1 | Language (Hindi): 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
  3. Section 1 | Language (उर्दू भाषा — 22 प्रश्न (निश्चित)): Spelling & Diacritics, Grammar (اسم, فعل, صفت, ضمیر), Vocabulary, Idioms & Proverbs, Comprehension
  4. Section 1 | Language (বাংলা / बांग्ला भाषा — 22 प्रश्न (निश्चित)): Bangla Script and Sounds, Bangla Grammar and Usage, Bangla Word Formation and Vocabulary, Reading and Text Interpretation
  5. Section 1 | Language (English): Vocabulary, Noun, Subject Verb Agreement (Verb Noun Agreement), Adjectives, Tenses, Pronoun, Verb, Adverb, Preposition, Articles, Determiner, Conjunction, Modals, Active Passive Voice (Voice), Direct and Indirect Speech, Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Construction, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Verbal Analogy (Word Based Analogy), Facts, Inference and Judgements
  6. Section 2 | Primary Maths & Reasoning: Ratio and Proportion (Ratios), Divisibility Rules, Mixture and Alligation, Permutation and Combination, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Percentage, Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Mensuration and Geometry, Age Problems, Arithmetic, Powers and Exponents (Surds and Indices), Algebra, Probability, Trigonometry, Syllogisms, Seating Arrangements, Blood Relations, Directions (Direction Test), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence
  7. Section 2 | General Awareness (GK + Current Affairs): Polity, Physics, Biology, State Wise GK, Chemistry, History, Geography, Indian Economy, Environment, GK- Current Affairs, Static General Knowledge
  8. Section 3 | Computer System and Org. (CSO): Basics of COA, Floating Point Rep, Cache Memory Organization, Instr Formats & Modes, Programming the Basic Computer, Input Output Organisation, Register Transfer and Microoperations, Control Unit Design
  9. Section 3 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, SQL, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control
  10. Section 3 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Process Synchronization
  11. Section 3 | Computer Networks: 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, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics
  12. Section 3 | Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Minimum Spanning Trees, Shortest Path Algos
  13. Section 3 | Theory Of Computation & Compiler Design: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization
  14. Section 3 | Emerging Trends (AI, Societal Ethics & MS Office): Artificial Intelligence, Emerging Tech Trends, Society, Law & Ethics, MS Office Applications
  15. Section 3 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Maintenance and Configuration Management, Software Testing
  16. Section 3 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  17. Section 3 | OOPS, C++, JAVA, HTML: OOPS with C++, Java, HTML Basics, CSS
  18. Section 3 | Java: Java Fundamentals, Array, String, IO & References
  19. Section 3 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  20. Section 3 | Digital Electronics: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  21. Section 3 | Multimedia: Multimedia
  22. BPSC Previous Year Papers:
  23. BPSC Full Mock Tests:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a comprehensive tutorial on solving "Train Problems," specifically focusing on "Case 4: Two Trains Moving In Same Direction." Presented by Yash Jain from Knowledge Gate Eduventures, the lecture begins by establishing the fundamental concepts of relative speed and total distance required for trains to cross each other. The instructor systematically works through three distinct numerical examples, demonstrating the step-by-step application of formulas, unit conversions between kilometers per hour and meters per second, and algebraic manipulation to find unknown variables such as time, length, and speed. The visual aids include on-screen text of the problems, handwritten calculations on a digital whiteboard, and diagrams illustrating train movements. The lesson is structured to take students from basic understanding to advanced problem-solving techniques, ensuring clarity in each step of the mathematical process.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with an introductory title card reading "PROBLEM ON TRAINS" and "Basic To Advance" by Yash Jain. It transitions to a slide titled "Case 4: Two Trains Moving In Same Direction," decorated with rocket and planet icons. The instructor explains the concept of relative speed when two objects move in the same direction, drawing arrows to indicate direction and writing "diff" to signify that the relative speed is the difference between the two speeds. He introduces the basic formula S = d/t (Speed = Distance / Time) as the foundation for solving these problems. He emphasizes that for trains moving in the same direction, the relative speed is calculated by subtracting the slower speed from the faster speed, a key distinction from opposite direction problems.

  2. 2:00 – 5:00 02:00-05:00

    The first numerical problem is introduced: "Two trains Bangalore Rajdhani (length 80 meters) and Gondwana Express (length 100 meters) are moving on parallel tracks in the same direction with speeds 90 kmph and 60 kmph. Find the time (in seconds) in which Bangalore Rajdhani will cross Gondwana Express completely." The instructor underlines the key values and calculates the relative speed as 90 - 60 = 30 kmph. He converts this to meters per second using the factor 5/18, resulting in 25/3 m/s. He then calculates the total distance as the sum of lengths (80 + 100 = 180 meters). Finally, he applies the formula t = d/s to find the time, resulting in 21.6 seconds. He writes out the calculation t = 180 / (25/3) = 180 x 3 / 25 = 108/5 = 21.6 sec on the board, showing the intermediate steps clearly.

  3. 5:00 – 10:00 05:00-10:00

    The second problem involves "Patalkot Express and Shreedham Express" moving in the same direction with speeds of 72 km/hr and 54 km/hr. They cross each other in 20 seconds, and the length of the faster train is 40 meters. The goal is to find the length of the slower train. The instructor converts the speeds to m/s (20 m/s and 15 m/s) and determines the relative speed is 5 m/s. He sets up the equation 5 = (40 + x) / 20, where x is the unknown length. Solving this, he finds the length of the slower train to be 60 meters. He writes the conversion steps clearly on the board, showing 72 x 5/18 = 20 and 54 x 5/18 = 15. An image of a train station sign reading "Shree Dham Jabalpur" is visible, adding context to the problem.

  4. 10:00 – 13:03 10:00-13:03

    The final problem features "Kaleen Express and Guddu Express" with lengths of 65 meters and 105 meters respectively. They cross each other in 51/2 seconds, and the speed of Kaleen Express is 84 kmph. The task is to find the speed of Guddu Express. The instructor calculates the total distance (170 meters) and the relative speed in m/s (20/3 m/s). He converts this relative speed to kmph (24 kmph). Using the relationship |84 - S2| = 24, he solves for the speed of Guddu Express, determining it to be 60 kmph. He writes the conversion from m/s to kmph as multiplying by 18/5. The instructor circles the final answer of 60 kmph to highlight the solution.

The video effectively guides students through the logic of relative motion for trains moving in the same direction. By breaking down the process into identifying given values, calculating relative speed (difference of speeds), summing the lengths for total distance, and applying the time-speed-distance formula, the instructor provides a clear methodology. The progression from finding time to finding length and finally finding speed demonstrates the versatility of the core concepts. The consistent use of unit conversion (5/18 factor) is emphasized as a critical step for accuracy in these problems. The instructor's handwritten notes on the digital whiteboard serve as a visual guide for students to follow along with the calculations, ensuring they understand the derivation of each result.

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