Short Tricks to Solve Dice Sum Problem (1)
Duration: 10 min
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Inside: a video lesson and guided study material.
Module outline
- Numerical Ability & Problem Solving: Speed Mathematics and Basic Mathematics, Arithmetic, Number System, HCF LCM, Divisibility Rules, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Mixture and Alligation, Time and Work, Pipe and Cistern, Speed Time and Distance, Age Problems, Partnership, Data Interpretation, Mental Ability, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Algebra, Statistics, Logarithm, Mensuration and Geometry, Permutation and Combination, Probability, Sequences and Series, Powers, Surds and Logarithms, Subject-Verb Agreement, Sentence Completion, Geometry, Sentence Structure and Correction, Data Sufficiency, Trigonometry, Measurement and Quantity Take-Off, Signal Space and Optimum Detection, Probability, Statistics, Algebra, Time and Work, Speed, Time and Distance, Data Interpretation, Combinatorics
- Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Blood Relations, Directions (Direction Test), Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Logical Sequence Of Words, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence, Selection Decision Table (Decision Making), Alphabet and Word Tests, Numerical Reasoning, Number System, Averages, Mixtures and Alligation, Percentages, Series Completion, Analogy and Classification, Patterns in Two-Dimensional Figures, Coding and Decoding, Mathematical Operations, Direction Sense, Logical Deduction and Induction, Syllogisms and Venn Diagrams, Critical Reasoning, Order, Ranking and Sequence, Reading Comprehension, Profit, Loss and Discount, Constraint Puzzles, Traverse Surveying, Ratio and Proportion, Mensuration, Permutations and Combinations, Clocks and Calendars, Assembling and Grouping of Shapes, Transformation of Shapes, Three-Dimensional Patterns and Visualization, Cubes and Dice, Vocabulary, Blood Relations
- General Knowledge & Current Affairs (India + Rajasthan): History, Geography, Polity, Indian Economy, Static General Knowledge, State Wise GK, GK- Current Affairs, Environment, Physics
- Computer Fundamentals & Operating Systems: Basics of COA, Floating Point Rep, Digital Systems & Boolean Basics, Number Representation, Number System, Introduction to OS, File Management, Windows OS, Unix OS, Linux OS, Register Transfer and Microoperations, Virtual Memory
- Computer Networks: Introduction to CN, Data Communication, DLL: Error Control, DLL: Access Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Application Layer, Hardware Basics, Network Security
- Cyber Security: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security, Ethical Hacking
- Programming (C & OOP): C Fundamentals, Control Flow, Arrays & Pointers, Functions, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Operators & Expressions, Sorting Algorithms, Java Fundamentals, Java
- MS Office & Data Processing: MS Office Applications, Basics of DBMS
- Internet & Web Technology: Society, Law & Ethics, Terms & Abbreviations, Keyboard Shortcuts, Emerging Tech Trends, Artificial Intelligence, Emerging Technologies, Internet Fundamentals, Website, Browser & Services, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security
AI summary & chapters
AI Summary
An AI-generated summary of this video lecture.
This educational video is a mathematics lecture that teaches how to solve problems involving the number of ways dice can sum to a specific value. The instructor begins by introducing the concept of permutations and combinations, using a visual metaphor of a detective trying to unlock a combination lock to explain the difference between the two. The main focus is on a 'Dice Sum Problem' where the goal is to find the number of ways three dice can sum to a given number. The video demonstrates a method using the stars and bars technique, which involves transforming the problem into finding the number of non-negative integer solutions to an equation. The instructor shows the general formula for this, n+r-1Cr, and applies it to the specific case of finding the number of ways to get a sum of 6 with three dice. The solution is derived by setting up the equation x1 + x2 + x3 = 6, where each xi represents the value on a die, and then applying the formula with n=6 and r=3. The video concludes with a similar example for a sum of 5, reinforcing the method. The lecture is presented on a digital whiteboard with the instructor visible in a small window, and the content is from 'Knowledge Gate Eduventures'.
Chapters
0:00 – 2:00 00:00-02:00
The video opens with a title card that visually distinguishes between 'PERMUTATION' and 'COMBINATION' using a casino theme (dice and roulette) and a business theme (fruit basket and office). This is followed by a slide titled 'Confused' which poses the question, 'Should I unlock with Permutation or Combination?'. The slide uses a detective metaphor, showing two locked doors labeled 'Permutation' and 'Combination', to illustrate the difference. The instructor, Yash Jain, is visible in a small window, and the 'Knowledge Gate Educator' logo is present. The video then transitions to a new slide titled 'Dice Sum Problem' with an image of two dice in a hand, setting up the main topic of the lecture.
2:00 – 5:00 02:00-05:00
The instructor presents the first problem: '3 dice are thrown, number of ways they can sum 6?'. He begins to solve it by setting up the equation x1 + x2 + x3 = 6, where x1, x2, and x3 are the values on the three dice. He notes that each die must show a value of at least 1, so x1 ≥ 1, x2 ≥ 1, x3 ≥ 1. To apply the standard formula for non-negative integer solutions, he introduces a substitution: x1' = x1 - 1, x2' = x2 - 1, x3' = x3 - 1. This transforms the equation into x1' + x2' + x3' = 3, where x1', x2', x3' ≥ 0. He then applies the formula for the number of non-negative integer solutions, which is n+r-1Cr, where n is the sum (3) and r is the number of variables (3). He writes the formula as 3+3-1C3, which simplifies to 5C3.
5:00 – 10:00 05:00-10:00
The instructor continues the calculation for the number of ways to get a sum of 6. He writes the formula 5C3 and then calculates it as 5! / (3! * 2!) = (5 * 4) / (2 * 1) = 10. He confirms that there are 10 ways. He then moves to a second example: 'If three dice are thrown, find the number of ways to get sum 5?'. He sets up the equation x1 + x2 + x3 = 5 with x1 ≥ 1, x2 ≥ 1, x3 ≥ 1. He applies the same substitution method, transforming it to x1' + x2' + x3' = 2. He then applies the formula n+r-1Cr with n=2 and r=3, which is 2+3-1C3 = 4C3. He calculates 4C3 as 4! / (3! * 1!) = 4. He concludes that there are 4 ways to get a sum of 5.
10:00 – 10:13 10:00-10:13
The video concludes with a black screen displaying the text 'THANKS FOR WATCHING' in white and orange. This is a standard closing slide for the educational content.
The video provides a clear, step-by-step tutorial on solving dice sum problems using combinatorics. It begins by establishing the foundational concept of permutations versus combinations, using a relatable metaphor. The core of the lesson is the application of the stars and bars method to find the number of integer solutions to an equation. The instructor demonstrates a systematic approach: first, setting up the equation for the sum, then adjusting for the constraint that each die must show a value of at least 1 by using a substitution, and finally applying the formula for combinations with repetition. The method is effectively demonstrated with two examples, first for a sum of 6 and then for a sum of 5, reinforcing the technique. The progression from a general problem to a specific, solved example makes the concept accessible for students preparing for competitive exams.