Check sibling questions

Example 8 - Aftab tells his daughter, Seven years ago I was

Example 8 - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 2
Example 8 - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 3

This video is only available for Teachoo black users

Maths Crash Course - Live lectures + all videos + Real time Doubt solving!


Transcript

Example 8 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.” (Isn’t this interesting?) Solve by the method of substitution.. We formed the equations in Ex 3.1, 1 The equations are x – 7y = −42 ...(1) x – 3y = 6 …(2) From (1) x – 7y = −42 x = 7y – 42 Putting value of x in (2) x – 3y = 6 (7y – 42) – 3y = 6 7y − 3y = 6 + 42 4y = 48 y = 48/4 y = 12 Putting y = 12 in equation (1) x – 7y = −42 x – 7(12) = −42 x − 84 = −42 x = −42 + 84 x = 42 So, x = 42, y = 12 is the solution of the equations Hence, Aftab’s age = x = 42 years His daughter’s age = y = 12 years

Ask a doubt (live)
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

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.