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Curated by: Khan Academy India - English (28 videos)
This video explores the classic probability problem of matching letters to their corresponding envelopes. We first analyze the scenario with 3 letters and 3 envelopes, calculating the total possible arrangements and then the probability that all letters go into the correct envelopes, and the probability that all letters go into incorrect envelopes (a concept known as derangements). We then extend this to a 4-letter, 4-envelope scenario. Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! (https://www.khanacademy.org/math/ncert-class-11/xea4762213f311c5e:probability-ncert-new/xea4762213f311c5e:axiomatic-approach-to-probability/e/sample-space) Timestamps: 00:00 Introduction: Probability of letters going into correct/incorrect envelopes 00:40 Scenario 1: 3 letters (A,B,C) and 3 corresponding envelopes. Total arrangements. 00:50 Problem 1a: Probability all letters are in correct envelopes. 01:10 Problem 1b: Probability all letters are in incorrect envelopes (derangements). 03:10 Scenario 2: 4 letters and 4 envelopes. P(all incorrect)? P(at least one correct)? Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by Ashish Gupta