Average - Short Tricks to Find Average Speed

Duration: 7 min

This video lesson is available to enrolled students.

Return to /learn/CDAC-C-CAT-COMPLETE-PREPARATION/section-a-aptitude/speed-time-and-distance/average-speed/asset-average-short-tricks-to-find-average-speed after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. Section A | English: Vocabulary, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Preposition, Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Articles, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Verbal Analogy (Word Based Analogy)
  2. Section A | Quant Aptitude: Ratio and Proportion (Ratios), Mixture and Alligation, Permutation and Combination, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Arithmetic, Algebra, Powers and Exponents (Surds and Indices), Average, Age Problems, Percentage, Profit and Loss, Partnership, Time and Work, Simple Interest and Compound Interest, Mensuration and Geometry, Probability, Pipe and Cistern
  3. Section A | Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Calendar, Clock, Blood Relations, Directions (Direction Test), Seating Arrangements, Ranking, Order and Sequence, Puzzle Solving (Puzzles)
  4. Section B | C Programming: C Programming by Yash Sir, Coding Questions by Yash Sir
  5. Section B | Data Structures: Algorithm Analysis, Greedy Algorithms, Time Complexity Analysis, Sorting Algorithms, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs
  6. Section B | OOP (C++): Object Oriented Programming (OOPS), Programming in C++
  7. Section B | OS: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS
  8. Section B | Networking: 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
  9. Section B | AI & Big Data Basics: AI & ML by Arun Sir, Big Data Systems
  10. Section C | Digital Electronics: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Analog-Digital Conversion
  11. Section A, C | Comp. Fundamentals, COA: Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations, Multiprocessors, Programming the Basic Computer
  12. MOCK TEST:
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.

Loading lesson…