Last updated at Jan. 17, 2020 by Teachoo

Transcript

Ex 3.2, 20 The bookshop of a particular school has 10 dozen chemistry books, 8 dozen physics books, 10 dozen economics books. Their selling prices are Rs 80, Rs 60 and Rs 40 each respectively. Find the total amount the bookshop will receive from selling all the books using matrix algebra. Number of chemistry books = 10 dozen = 10 × 12 = 120 Number of physics books = 8 dozen = 8 × 12 = 96 Number of economics books = 10 dozen = 10 × 12 = 120 Let matrix A denote the number of books per subject. A = [ 120 96 120 ] Let Matrix B denote the selling price of books per subject B = [█(80@60@40)] Now, Total amount the shopkeeper receives = Number of books × Selling price = AB = 〖"[ 120 96 120 ]" 〗_(1 × 3) [■8(80@60@40)]_(3 × 1) = 〖["120 × 80 + 96 × 60 + 120 × 40" ]〗_(1 × 1) = "120 × 80 + 96 × 60 + 120 × 40" = 9600 + 5760 + 4800 Chemistry = 20160 Hence, total amount received by shopkeeper is Rs. 20,160

Statement questions - Multiplication of matrices

Chapter 3 Class 12 Matrices

Concept wise

- Formation and order of matrix
- Types of matrices
- Equal matrices
- Addition/ subtraction of matrices
- Statement questions - Addition/Subtraction of matrices
- Multiplication of matrices
- Statement questions - Multiplication of matrices
- Solving Equation
- Finding unknown - Element
- Finding unknown - Matrice
- Transpose of a matrix
- Symmetric and skew symmetric matrices
- Proof using property of transpose
- Inverse of matrix using elementary transformation
- Proof using mathematical induction

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.