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Ex 3.1, 1 Class 10 - NCERT Solutions Maths - Aftab tells his daughter

Ex 3.1, 1 - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 2
Ex 3.1, 1 - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 3 Ex 3.1, 1 - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 4 Ex 3.1, 1 - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 5 Ex 3.1, 1 - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 6

 

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Ex 3.1, 1 Aftab tells his daughter, “Seven years ago, I was seven times as old as you were then. Also, three years from now, I shall be three times as old as you will be.” Represent this situation algebraically & graphically. Let the Current age of Aftab be x years. & let Current age of Aftab’s daughter be y years. Given that “Seven years ago, I was seven times as old as you were then” Seven years ago, Age of Aftab = x − 7 Age of Aftab’s daughter = y − 7 Aftab was seven times as old as Aftab’s daughter (x – 7) = 7(y – 7) (x – 7) = 7y – 49 x – 7y = 7 − 49 x – 7y = −42 Also, “three years from now, I shall be three times as old as you will be “ Three years later, Age of Aftab = x + 3 Age of Aftab’s daughter = y + 3 Aftab will be three times as Aftab’s daughter (x + 3) = 3(y + 3) (x + 3) = 3y + 9 x – 3y = 9 − 3 x – 3y = 6 So, our equations are x – 7y = −42 ...(1) x – 3y = 6 For Equation (1) x – 7y = −42 Let x = 0 0 − 7y = −42 −7y = −42 y = (−42)/(−7) y = 6 So, x = 0, y = 6 is a solution i.e. (0, 6) is a solution Let x = 7 7 − 7y = −42 −7y = −42 − 7 y = (−49)/(−7) y = 7 So, x = 7, y = 7 is a solution i.e. (7, 7) is a solution For Equation (2) x − 3y = 6 Putting x = 0 0 − 3y = 6 −3y = 6 y = 6/(−3) y = −2 So, x = 0, y = −2 is a solution i.e. (0, −2) is a solution Putting y = 0 x − 3(0) = 6 x – 0 = 6 x = 6 So, x = 6, y = 0 is a solution i.e. (6, 0) is a solution We will plot both equations on the graph

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.