in a class test the sum of the marks obtained by p in mathematics and sciene is 28. had he got 3 marks more in mathematics and 4 marks less in science the product of his marks would have been 180. find the marks in the two subjects.
Answers
Answered by
864
Let the marks obtained in mathematics be x then marks in science be 28-x
acc,
(x+3)(28-x-4)=180
⇒(x+3)(24-x)=180
⇒24x-x²+72-3x=180
⇒21x-x²-180=0
⇒x²-21x+180=0
⇒x²-12x-9x+108=0
⇒x(x-12)-9(x-12)=0
⇒(x-9)(x-12)=0
∴x=9,12
the marks scored in maths can be 9 or 12
if she got 12 in maths then she got 28-12=16 in science
if she got 9 in maths then she got 28-9=19 in science
hope it helps u
acc,
(x+3)(28-x-4)=180
⇒(x+3)(24-x)=180
⇒24x-x²+72-3x=180
⇒21x-x²-180=0
⇒x²-21x+180=0
⇒x²-12x-9x+108=0
⇒x(x-12)-9(x-12)=0
⇒(x-9)(x-12)=0
∴x=9,12
the marks scored in maths can be 9 or 12
if she got 12 in maths then she got 28-12=16 in science
if she got 9 in maths then she got 28-9=19 in science
hope it helps u
karishmad:
thanks
Answered by
192
SOLUTION :
Let the marks obtained by P in Maths be x.
Then, the marks in science will be 28 - x.
A.T.Q
(x + 3)(28 - x - 4) = 180
(x + 3)(24 - x) = 180
24x - x² + 72 - 3x = 180
-x² + 21x + 72 - 180 = 0
-x² + 21x + 72 - 108 = 0
x² - 21x + 108 = 0
x² - 12x - 9x + 108 = 0
[By middle term splitting]
x(x - 12) - 9(x - 12) = 0
(x - 12) (x - 9) = 0
(x - 12) = 0 or (x - 9) = 0
x = 12 or x = 9
Case 1 :
If the marks in Maths are 12, then marks in science will be = 28 - x = 28 - 12 = 16
Case 2:
If the marks in Maths are 9, then marks in science will be 28 - 9 = 19
Hence, the marks in Maths are (12,9) and marks in science are (16,19)
HOPE THIS ANSWER WILL HELP YOU.
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