WE - Using AND and OR (constraints) | Permutations and Combinations | Grade 11 | Math | Khan Academy

In this video, we solve some worked examples involving problems related to rearrangement of digits with constraints. We first find even numbers for both scenarios - repetition allowed and repetition not allowed. We then solve a similar problem where we need to find the total number of odd numbers. We then solve a problem where we need to find the total number of telephone numbers. Important thing to note is that telephone numbers have no problem starting with zero. Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! (https://www.khanacademy.org/math/ncer...) Timestamps: 00:00 Problem 1 (even numbers) 00:34 Solution part 1 (repetition allowed) 01:37 Solution part 2 (repetition not allowed) 02:20 Problem 2 (odd numbers) 02:54 Solution part 1 (repetition allowed) 03:36 Solution part 2 (repetition not allowed) 04:24 Problem 3 (telephone numbers) 05:03 Solution (dealing with constraints first) 06:03 Problem 4 (even telephone numbers) 06:22 Solution (dealing with constraints first) 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