The best way for solving the question of quadratic equation of exercise 4.3. What are the way that i easily solve this 10th class question 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.
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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. Q.5
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Let us say, the marks of Shefali in Maths be x.
Then, the marks in English will be 30 – x.
As per the given question,
(x + 2)(30 – x – 3) = 210
(x + 2)(27 – x) = 210
⇒ -x2 + 25x + 54 = 210
⇒ x2 – 25x + 156 = 0
⇒ x2 – 12x – 13x + 156 = 0
⇒ x(x – 12) -13(x – 12) = 0
⇒ (x – 12)(x – 13) = 0
⇒ x = 12, 13
Therefore, if the marks in Maths are 12, then marks in English will be 30 – 12 = 18 and the marks in Maths are 13, then marks in English will be 30 – 13 = 17.