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

Examples

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Example 16 Important Deleted for CBSE Board 2023 Exams

Example 17 Deleted for CBSE Board 2023 Exams

Example 18 Important Deleted for CBSE Board 2023 Exams

Example 19 Important Deleted for CBSE Board 2023 Exams

Last updated at Dec. 18, 2020 by Teachoo

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

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