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Ex 4.3, 5 - In a class test, sum of Shefali marks in maths - Ex 4.3

Ex 4.3, 5 - Chapter 4 Class 10 Quadratic Equations - Part 2
Ex 4.3, 5 - Chapter 4 Class 10 Quadratic Equations - Part 3

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Ex 4.3 ,5 In a class test, the sum of Shefali s marks in Mathematics and English is 30. Had she got 2 marks more in Mathematics and 3 marks less in English, the product of their marks would have been 210. Find her marks in the two subjects. Let shefali s marks in mathematics = x Given that sum of Shefali s marks in English and Mathematics is 30 Marks in mathematics + Marks in English = 30 x + Marks in English = 30 Marks in English = 30 x Also, it is given that had she got 2 marks more in mathematics and 3 marks less in English, the product of their marks would have been 210 (Marks in Maths + 2) (Marks in English 3) = 210 (x + 2) (30 x 3) = 210 (x + 2) (27 x ) = 210 x (27 x) + 2 (27 x) = 210 27x x2 + 54 2x = 210 27x x2 + 54 2x 210 = 0 x2 2x + 27x + 54 210 = 0 x2 + 25x 156 = 0 0 = x2 25x + 156 x2 25x + 156 = 0 We factorize by splitting the middle term method x2 12x 13x + 156 = 0 x (x 12) 13 (x 12) = 0 (x 13) (x 12) = 0 Therefore x = 13, x = 12 are the roots of the given equation Assuming x = 12, Marks in maths = x = 12 Marks in English = 30 x = 30 12 = 18

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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.