Permutations
Chapter Name : Permutations And Combinations |
Sub Topic Code : 104_11_07_03_03 |
Topic Name : Permutations |
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Sub Topic Name : Derivation Of The Formula For 'P' |
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Introduction
• As we know the expression of permutation nPr is lengthy so to reduce the size of this expression the notation factorial is used. • Factorial of a number is the product of all numbers from 1 to that number. • We use the factorial notation and derive the formula for p.
Pre-Requisites:
• Knowledge of fundamental principle of counting. • Knowledge of permutations. • Knowledge of factorial.
Activity:
By shuffling the blocks find in how many ways you can arrange different combination of blocks.
Real Life Question:
How many unique study hours for Math, Physics and Chemistry you can schedule for your exams if you are planning single subject a week?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Permutations | Permutation is an arrangement of number or object in definite order. |
| Factorial | Product of all numbers from 1 to that number. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Different color blocks Of block game. | Take 4 different colors of blocks. Shuffle the blocks in such a way that each combination of block is unique. |
Real life uses :
Permutations are used in allotting mobile numbers.
Places to visit :
Look for 3 chairs and find out in how many different ways can 7 people sit in 3 chairs?
Practical examples around us
| Examples | Explainations |
|---|---|
| In how many ways you can vote for your school elections for captain and vice-captain from a group of 5 selected candidates? | This question is asking us to select 2 persons from a group of 5.Here n= 5 and r=2. |
What you learn in Theory:
Permutations are used when we want to find number of ways an event can occur.
What you learn in Practice:
Permutations are used to solve many problems on probability, genetic engineering.