# Ex 3.2, 1 - Chapter 3 Class 10 Pair of Linear Equations in Two Variables (Important Question)

Last updated at July 18, 2019 by Teachoo

Last updated at July 18, 2019 by Teachoo

Transcript

Ex 3.2,1 Form the pair of linear equations in the following problems & find their solutions graphically 10 students of Class X took part in a Mathematics quiz. If the number of girls is 4 more than the number of boys, find the number of boys and girls who took part in the quiz. Let the number of girls who took part in the quiz be x. & Let the number of boys who took part in the quiz be y. Total 10 students took part in the quiz (Number of girls who took part in the quiz) + (Number of boys who took part in the quiz) x + y = 10 x + y – 10 = 0 Also, number of girls is 4 more than boys Number of girls = 4 + Number of boys or x = 4 + y x – y − 4 = 0 Now, plotting equations x + y −10 = 0 ...(1) x − y – 4 = 0 …(2) Solving (1) x + y – 10 = 0 y = 10 − x Solving (2) x − y – 4 = 0 y = x – 4 Ex 3.2,1 Form the pair of linear equations in the following problems & find their solutions graphically (ii) 5 pencils and 7 pens together cost Rs. 50 , whereas 7 pencils and 5 pens together cost Rs. 46. Find the cost of one pencil and that of one pen Let the cost of one pencil be x. & Let the cost of one pen be y. 5 pencils and 7 pens together cost Rs 50 5 × (Cost of pencil) + 7 × (Cost of pens) = 50 or 5x + 7y = 50 5x + 7y – 50 = 0 Also,7 pencils and 5 pens together cost Rs. 46 7 × (Cost of pencil) + 5 × (Cost of pen) = 46 or 7x + 5y = 46 7x + 5y – 46 = 0 Now, plotting equations 5x + 7y – 50 = 0 ...(1) 7x + 5y – 46 = 0 …(2) Solving (1) 5x + 7y – 50 = 0 7y = 50 – 5x y = (50 − 5𝑥)/7 Solving (2) 7x + 5y – 46 = 0 5y = 46 – 7x y = (46 −7𝑥)/5

Chapter 3 Class 10 Pair of Linear Equations in Two Variables

Example 6
Important

Example 10 Important

Example 11 Important

Example 13 Important

Example 14 Important

Example 19 Important

Ex 3.2, 1 Important You are here

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 9 years. He provides courses for Maths and Science at Teachoo.