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

Duration: 6 min

This video lesson is available to enrolled students.

Return to /learn/WIPRO-PREPARATION/quantitative-aptitude/ratio-and-proportion-ratios/successive-combined-ratio-problems/asset-short-trick-to-find-a-c-when-a-b-b-c-is-given after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. Quantitative Aptitude: Number System, Percentage, Profit and Loss, Ratio and Proportion (Ratios), Average, Time and Work, Speed Time and Distance, Simple Interest and Compound Interest, Mixture and Alligation, Data Interpretation, Permutation and Combination, Probability, Logarithm, Powers and Exponents (Surds and Indices), Age Problems, Divisibility Rules, Partnership, HCF LCM, Algebra, Pipe and Cistern
  2. Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Analogy, Coding Decoding, Blood Relations, Directions (Direction Test), Syllogisms, Logical Sequence Of Words, Data Sufficiency, Seating Arrangements, Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Data Arrangement
  3. English Language: Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Vocabulary, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Active Passive Voice (Voice), Direct and Indirect Speech, Cloze Test (Cloze Passage), Tenses, Subject Verb Agreement (Verb Noun Agreement), Preposition, Articles, Conjunction, Adverb
  4. Written English Test: English Writing Ability
  5. Coding: Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Java, Python for Placements by Yash Sir
  6. Communication Round: Communication Assessment
  7. DBMS (Technical Interview): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, ORDBMS, Database Security & Authorization, Query Processing & Optimization, Enhanced Data Models, Big Data Systems, NoSQL, Data Warehousing & Mining
  8. SQL (Technical Interview): SQL
  9. Operating Systems (Technical Interview): Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Linux OS, Security, Distributed Systems, Virtual Machines
  10. Computer Networks (Technical Interview): Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, 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, Mobile Technology, Cloud Computing and IoT, Cyber and Info Security
  11. OOPs (Technical Interview): Object Oriented Programming (OOPS)
  12. HR Interview: MR & HR Interview Preparation
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.

Loading lesson…