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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4
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
⇒ -x^2 + 25x + 54 = 210
⇒ x^2 – 25x + 156 = 0
⇒ x^2 – 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.
Answered by
1
Answer:
- let maths marks=x,and english=y
- so ATQ(according to question),
- x+y=30(given)-------(1)
- (x+2)(y-3)=210--------(2)
- from(1)x=30-y---------(3) put into (2)
- (30-y+2)(y-3)=210
- (32-y)(y-3)=210
- 32y-96-y^2+3y=210
- y^2-35y+96=-210
- y^2-32y-3y+96=-210
- y(y-32)-3(y-32)=-210
- (y-3)(y-32)=-210
- y=-207,-188
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