# Example 11

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Example 11 The ratio of incomes of two persons is 9 : 7 and the ratio of their expenditures is 4 : 3. If each of them manages to save Rs.2000 per month, find their monthly incomes. It is given that , Ratio of income of two persons is 9:7 Let the income of 1st person be 9x & income for 2nd person be 7x. Similarly, Ratio of expenditures of two persons is 4 : 3 Let expenditure of 1st person be 4y & expenditure of 2nd person be 3y Both saves Rs 2000 per month Both saves Rs 2000 per month We know that, Income Expenditure = Savings For 1st person 9x 4y = 2000 Similarly for 2nd person 7x 3y = 2000 Now, our equations are 9x 4y = 2000 (1) 7x 3y = 2000 (2) We will solve them by elimination We know that 12 is the multiple of 3 and 4 Multiplying (1) with 3 3 ( 9x 4y) = 2000 3 27x 12y = 6000 Now we use elimination with equation (3) & (4) x = 2000 x = 2000 Putting value of x in (1) 9x 4y = 2000 9(2000) 4y = 2000 18000 4y = 2000 - 4y = 2000 18000 - 4y = - 16000 y = 16000/4 y = 4000 Hence, x = 2000, y = 4000 is the solution of the equation . Hence, Monthly income of 1st person = 9x = 9 2000 = Rs 18,000 Monthly income of 2nd person = 7x = 7 2000 = Rs 14,000

Chapter 3 Class 10 Pair of Linear Equations in Two Variables

Example 6
Important

Example 10 Important

Example 11 Important You are here

Example 13 Important

Example 14 Important

Example 19 Important

Ex 3.2, 1 Important

Ex 3.2, 3 Important

Ex 3.2, 6 Important

Ex 3.2, 7 Important

Ex 3.5, 2 Important

Ex 3.6, 1 (i) and (ii) Important

Ex 3.6, 1 (iii) and (iv) Important

Ex 3.6, 1 (v) and (vi) Important

Ex 3.6, 1 (vii) and (viii) Important

Ex 3.6, 2 Important

Class 10

Important Questions for Exam - Class 10

- Chapter 1 Class 10 Real Numbers
- Chapter 2 Class 10 Polynomials
- Chapter 3 Class 10 Pair of Linear Equations in Two Variables
- Chapter 4 Class 10 Quadratic Equations
- Chapter 5 Class 10 Arithmetic Progressions
- Chapter 6 Class 10 Triangles
- Chapter 7 Class 10 Coordinate Geometry
- Chapter 8 Class 10 Introduction to Trignometry
- Chapter 9 Class 10 Some Applications of Trignometry
- Chapter 10 Class 10 Circles
- Chapter 11 Class 10 Constructions
- Chapter 12 Class 10 Areas related to Circles
- Chapter 13 Class 10 Surface Areas and Volumes
- Chapter 14 Class 10 Statistics
- Chapter 15 Class 10 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.