# Example 19

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Example 19 In a legislative assembly election, a political group hired a public relations firm to promote its candidate in three ways: telephone, house calls, and letters. The cost per contact (in paise) is given in matrix A as A = [■8( 40 @100@50)] The number of contacts of each type made in two cities X and Y is given by B = [■8(1000& 500 &5000@3000&1000&10,000)] Find the total amount spent by the group in the two cities X and Y. We need to calculate total amount spent by the group in two cities x & y Total amount spent = Number of contact × Cost per contact = BA = [■8(1000&500&5000@3000&1000&10,000)]_(2 × 3) [■8(40@100@50)]_(3 × 1) = [█(1000(40)+500(100)+5000(50)@3000(40)+1000(100)+10,000(50))]_(2 × 1) = [█(40,000+50,000+250,000@120,000+100,000+500,000)] = [█(340,000@720,000)] Hence, total amount spent = [█(340,000@720,000)] So the total amount spent by the group in city X = 340,000 paise = Rs. 3400 So the total amount spent by the group in city X = 720,000 paise = Rs. 7200

Chapter 3 Class 12 Matrices

Ex 3.1, 7
Important

Ex 3.1, 9 Important

Example 18 Important

Example 19 Important You are here

Ex 3.2, 7 Important

Ex 3.2, 12 Important

Ex 3.2, 16 Important

Ex 3.2, 17 Important

Ex 3.2, 20 Important

Example 22 Important

Ex 3.3, 4 Important

Ex 3.3, 10 Important

Ex 3.3, 12 Important

Ex 3.4, 15 Important

Ex 3.4, 17 Important

Example 28 Important

Misc. 3 Important

Misc. 9 Important

Misc. 11 Important

Misc. 13 Important

Class 12

Important Question for exams Class 12

- Chapter 1 Class 12 Relation and Functions
- Chapter 2 Class 12 Inverse Trigonometric Functions
- Chapter 3 Class 12 Matrices
- Chapter 4 Class 12 Determinants
- Chapter 5 Class 12 Continuity and Differentiability
- Chapter 6 Class 12 Application of Derivatives
- Chapter 7 Class 12 Integrals
- Chapter 8 Class 12 Application of Integrals
- Chapter 9 Class 12 Differential Equations
- Chapter 10 Class 12 Vector Algebra
- Chapter 11 Class 12 Three Dimensional Geometry
- Chapter 12 Class 12 Linear Programming
- Chapter 13 Class 12 Probability

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.