Short Trick to Find A C when A B & B C is given

Duration: 6 min

This video lesson is available to enrolled students.

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  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
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  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, Number System & Place Value, Factors, Multiples, Divisibility, HCF & LCM, Coordinates & Graphs, Higher Mathematics — Trigonometry, Quadratics, Polynomials, Progressions, Statistics, Logarithms
  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
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  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, Marketing and Consumer Studies, साइबर सुरक्षा / Cyber Safety and Security, कंप्यूटर सॉफ़्टवेयर / Computer Software, ऑपरेटिंग सिस्टम / Operating System, कंप्यूटर नेटवर्क / Computer Networks, वर्ड प्रोसेसिंग (MS Word) / Word Processing (MS Word), Terms & Abbreviations, प्रेज़ेंटेशन (MS PowerPoint) / Presentation Software (MS PowerPoint)
  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
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  17. Section 3 | OOPS, C++, JAVA, HTML: OOPS with C++, Java, HTML Basics, CSS
  18. Section 3 | Java: Java Fundamentals, Array, String, IO & References, OOPS with Java
  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 step-by-step guide to solving ratio problems, specifically focusing on finding the combined ratio A:C when given two separate ratios A:B and B:C. The instructor begins by defining a ratio as a comparison of two quantities and then presents a specific problem: If A:B = 3:4 and B:C = 6:7, find A:C. He demonstrates the standard method of equating the common term B using the Least Common Multiple (LCM). He then introduces a faster shortcut method involving the multiplication of fractions. The lesson is reinforced with a second example and a review of the first problem using the shortcut, ensuring students understand both the conceptual and procedural aspects of the topic.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video begins with a title slide "RATIO & PROPORTION" followed by a definition card stating "Ratio a comparison of 2 quantities". The instructor then presents the core problem: "If A : B = 3 : 4 and B : C = 6 : 7, find A : C?". He writes the ratios vertically, underlining the common term B in both. He explains that to combine them, the value of B must be the same in both ratios. He identifies the Least Common Multiple (LCM) of 4 and 6 as 12. To achieve this, he multiplies the entire first ratio (3:4) by 3, resulting in 9:12. Simultaneously, he multiplies the second ratio (6:7) by 2, resulting in 12:14. This aligns the ratios to form a combined sequence A:B:C as 9:12:14. Consequently, the ratio of A to C is derived as 9:14.

  2. 2:00 – 5:00 02:00-05:00

    Next, a second example is introduced: "If A : B = 4 : 7 and B : C = 2 : 3, find A : C?". The instructor repeats the process of aligning the common term B. He notes the LCM of 7 and 2 is 14. He multiplies the first ratio (4:7) by 2 to get 8:14 and the second ratio (2:3) by 7 to get 14:21. This creates the combined ratio A:B:C as 8:14:21, yielding A:C = 8:21. He then introduces a shortcut method, writing the equation A/C = (A/B) x (B/C). He substitutes the fractions 4/7 and 2/3 into the equation. The multiplication yields 8/21, confirming the previous result. This method is highlighted as a quicker alternative to finding LCMs.

  3. 5:00 – 6:03 05:00-06:03

    The instructor returns to the first problem to demonstrate the shortcut method in detail. He writes the equation A/B x B/C = A/C. He substitutes the values 3/4 and 6/7. He explicitly shows the cross-simplification step where the 6 in the numerator and the 4 in the denominator are both divided by 2. This simplifies the expression to (3/2) x (3/7). The final multiplication gives 9/14. He circles the final answer to emphasize correctness. The video concludes with a black screen displaying "THANKS FOR WATCHING" in orange and white text, signaling the end of the lesson on combining ratios.

The lesson effectively bridges the gap between basic ratio definitions and more complex combined ratio problems. By first establishing the need for a common term (B) and then introducing the fraction multiplication shortcut, the instructor provides students with two distinct strategies. The visual progression from vertical alignment to fraction multiplication reinforces the mathematical logic behind the operations.

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